I beg this is the real episode list~

A New Adventure

Characters: Emma Gilbert, Cleo Sertori, Rikki Chadwick, Bella Hartley, Kelly Smith, Lewis McCartney, Will Benjamin, Zane Bennett, Sophie Benjamin, Charlotte Watsford, Nate, Kim Sertori, Gracie Watsford, Julia Dove

Plot: Emma returns and makes friends with Bella. The girls use their magic to heal the moon pool and restore it to its original form. The Water Tentacle is missing and the girls suggest that the tentacle has stopped attacking the mermaids after they prevented the comet from collision. Charlotte returns and admits to the girls that she has changed her personality as an apology to them for being so mean. There's a new girl in town, Kelly Smith. When the full moon rises, something strange happens and a mysterious wind attacks Cleo and Emma. At Rikki's Cafe, the same wind attacks again and it throws Cleo to the water. The wind transforms into... Gracie and Julia! They reveal that they want to kill the mermaids, steal their powers and reveal their secret to the whole world. During a battle, Kelly reveals that she's a mermaid and has a power to blow water. However, the girls' crystals begin to act strangely and release a strange force which defeats Gracie and Julia. They vow to return in the next full moon. At the end, Kelly tells everyone that she found the moon pool under the Niagara Falls and turned into a mermaid there when she was 12. The girls accept her in the mermaid club.

Note: Claire Holt returns to H2O in this season. Angus McLaren has agreed to guest star in few episodes of the season. Hannah Murray joins the main cast for this season.
Life in College Life in College section

Characters: Emma Gilbert, Cleo Sertori, Rikki Chadwick, Bella Hartley, Kelly Smith, Will Benjamin, Bryan Anderson, Zane Bennett, Sophie Benjamin, Charlotte Watsford, Kim Sertori, Don Sertori, Samantha Roberts-Sertori, Elliot Gilbert, Lisa Gilbert, Neil Gilbert, Mr. Olsen, Mrs. Pitts

Plot: The girls start to attend the college in Gold Coast and try to adjust to college life, but with little successes. Kelly meets Bryan Anderson and gets a crush on him. Meanwhile, Cleo goes to Mako Island to figure out the strange power of the crystals. She finds out that the crystals have gained a new and strong power during the recovery of the moon pool.

Note: Bryan Anderson is played by Liam Hemsworth.
The End of the Marine Park The End of the Marine Park section

Characters: Emma Gilbert, Cleo Sertori, Rikki Chadwick, Bella Hartley, Kelly Smith, Will Benjamin, Bryan Anderson, Don Sertori, Mrs Geddes, Laurie, Ronnie

Plot: The marine park is getting close to bankrupt. Cleo gets upset to find out and doesn't want to lose her job. She opens a sale to earn money to save the marine park. Meanwhile, Kelly tries to get close to Bryan and goes to Emma, Rikki and Bella for advice.
Kelly's Birthday Kelly's Birthday section

Characters: Emma Gilbert, Cleo Sertori, Rikki Chadwick, Bella Hartley, Kelly Smith, Will Benjamin, Bryan Anderson, Zane Bennett, Sophie Benjamin, Charlotte Watsford, Nate, Fred Smith, Irene Smith

Plot: Kelly's 19th birthday are coming up. Cleo promises to Kelly that she won't organize a surprise party. Rikki decides to organize the party, along with Emma and Bella. Kelly gets upset to see the surprise party and runs away from home. Bryan finds Kelly and she realizes that he's also in the party, so she comes back.
Return of AshEdit Return of Ash sectionEdit

Characters: Emma Gilbert, Cleo Sertori, Rikki Chadwick, Bella Hartley, Kelly Smith, Will Benjamin, Ash Dove

Plot: Emma finds out that Ash has come back and is a new polo player. She comes to see him. Ash tells Emma that he has to win the upcoming polo match. Emma finds out that Ash has a sharp competition and is worried about him. Cleo, Rikki, Bella and Kelly tell her to not to worry. Ash wins the match and takes Emma for a ride.
Families in College Families in College section

Characters: Emma Gilbert, Cleo Sertori, Rikki Chadwick, Bella Hartley, Kelly Smith, Will Benjamin, Bryan Anderson, Zane Bennett, Sophie Benjamin, Charlotte Watsford, Kim Sertori, Don Sertori, Samantha Roberts-Sertori, Bev Sertori, Elliot Gilbert, Lisa Gilbert, Neil Gilbert, Terry Chadwick, Tom Hartley, Wendy Hartley, Harrison Bennett, Fred Smith, Irene Smith, William Anderson, Lilly Anderson

Plot: The college organizes a night for the families. Cleo is in shock to find out that her mother has returned for the night and seems to not get along with Sam. Cleo tries to make both her mothers up and succeeds. Meanwhile, the rest of the girls are having problems with their parents and Kelly is unsure that her parents will accept Bryan.
Return of Dr. DangerE Return of Dr. Danger section

Characters: Emma Gilbert, Cleo Sertori, Rikki Chadwick, Bella Hartley, Kelly Smith, Lewis McCartney, Will Benjamin, Dr. Linda Denman

Plot: Lewis returns to town for few days. He's not the only one who returned; Dr. Denman also returned to check on the growing seaweeds. The girls are worried that Dr. Denman will find out that they're still mermaids and there are two new mermaids. One of Dr. Denman's cameras exposes the girls. Dr. Denman kidnaps Emma, Rikki, Bella and Kelly for research. Cleo, Lewis and Will go save them. Lewis tells Dr. Denman that the girls need to protect themselves and nobody can't find out that they're mermaids. Dr. Denman decides to leave the girls alone and departs.
Mermaid FightEdit Mermaid Fight sectionEdit

Characters: Emma Gilbert, Cleo Sertori, Rikki Chadwick, Bella Hartley, Kelly Smith, Will Benjamin, Gracie Watsford, Julia Dove, Louise Chatham, Max Hamilton, Fred Smith, Irene Smith

Plot: With the another full moon approaching, the girls go with Kelly's family for a weekend to the beach. The girls try to hide from Kelly's parents that they're mermaids. However, when the moon rises, something strange happens which causes the girls to argue with each other. Miss Chatham and Max arrive and tell the girls that they lost their harmony. They demand crystals. Rikki sees that Miss Chatham and Max's shadows are different. Miss Chatham and Max reveal to be Gracie and Julia. The girls manage to defeat Gracie and Julia, who then escape, and agree to not fight more.
Evil SophieEdit Evil Sophie sectionEdit

Characters: Emma Gilbert, Cleo Sertori, Rikki Chadwick, Bella Hartley, Kelly Smith, Will Benjamin, Zane Bennett, Sophie Benjamin, Kim Sertori, Samantha Roberts-Sertori, Ryan Tate

Plot: Sophie starts to act strictly to the cafe's workers. Zane needs two new waitresses. Rikki starts to think that she made a mistake with breaking up with Zane. Meanwhile, Cleo finds out that Ryan has returned. Sophie and Ryan accidentally discover the girls' secret. Sophie tries to reveal it to everyone to gain more and more money, but Will stops her. Zane fires Sophie from the cafe for acting so strictly to the workers and nearly exposing the girls' secret. Rikki and Zane get back together and Rikki replaces Sophie as Zane's business partner. Sophie and Ryan promise to keep the girls' secret. Sophie gets rehired to the cafe as a waitress and Rikki hires Emma to the cafe as the second waitress.
Another Mermaid MonsterEdit Another Mermaid Monster sectionEdit

Characters: Emma Gilbert, Cleo Sertori, Rikki Chadwick, Bella Hartley, Kelly Smith, Will Benjamin, Zane Bennett, Sophie Benjamin, Charlotte Watsford, Nate, Tom Hartley, Wendy Hartley

Plot: While swimming with Will, Bella cuts her shoulder with a seaweed. Emma starts to worry about that. During a rehearsal at the cafe, Bella suddenly passes out and the girls and Will take her home. Bella's skin starts to become green and green. Emma becomes panicked because she was previously poisoned. Cleo checks the piece of the seaweed and discovers that it's poisonous. Bella's skin gets more green and she transforms to a monster. Even worse, her parents return early from their date, but Cleo manages to find a way to find the antidote and cure Bella on time.
Journey to the Center of AustraliaEdit Journey to the Center of Australia sectionEdit

Characters: Emma Gilbert, Cleo Sertori, Rikki Chadwick, Bella Hartley, Kelly Smith, Will Benjamin, Bryan Anderson, Zane Bennett, Charlotte Watsford, Mr. Olsen

Plot: The girls' university class goes for a trip to the deserts of the middle Australia. Kelly gets paired with Bryan to do an assignment about the kangaroos. Rikki gets worried because of Kelly's crush on Bryan and it will expose her secret. Luckily, Kelly didn't expose her secret.
A New CoupleEdit A New Couple sectionEdit

Characters: Emma Gilbert, Cleo Sertori, Rikki Chadwick, Bella Hartley, Kelly Smith, Will Benjamin, Bryan Anderson, Charlotte Watsford, Fred Smith, Irene Smith

Plot: Kelly is eager to start a relationship with Bryan. Bryan feels the same. The girls agree to help her organize a date. With Kelly's parents out for a night, she uses this as an opportunity to have a date with Bryan. During the date, Bryan accidentally spills the drink on Kelly and she jumps to the water, making Bryan feel disappointed and leave. At the end of the episode, Kelly apologizes for ruining their date and confesses to him her feelings. Bryan also confesses his feelings and he and Kelly kiss, starting their anticipated relationship.
Dream FightEdit Dream Fight sectionEdit

Characters: Emma Gilbert, Cleo Sertori, Rikki Chadwick, Bella Hartley, Kelly Smith, Lewis McCartney, Will Benjamin, Bryan Anderson, Zane Bennett, Sophie Benjamin, Charlotte Watsford, Nate, Kim Sertori, Don Sertori, Samantha Roberts-Sertori, Gracie Watsford, Julia Dove, Mr. Olsen

Plot: With the another full moon approaching, the girls are eager to study for the upcoming exam, but are worried about the another Gracie and Julia's attack. While talking through the webcam, Lewis tells Cleo to be careful. When the moon rises, nothing happens and Gracie and Julia didn't arrive. The girls don't need to worry and begin to study. While studying, the girls fall asleep and have the nightmares. Cleo eventually realizes that she the girls have nightmares because someone is physically entering to their dreams. The girls sleep in one room and, in the dream, discover that Gracie and Julia were behind all this. The girls, transformed into their powers, defeat Gracie and Julia and wake up.
Record DealEdit Record Deal sectionEdit

Characters: Emma Gilbert, Cleo Sertori, Rikki Chadwick, Bella Hartley, Kelly Smith, Will Benjamin, Bryan Anderson, Zane Bennett, Sophie Benjamin, Nate, Elliot Gilbert, Parlophone Records manager

Plot: Bella, Nate and their band are approached by the manager of Parlophone Records, who offers them a record deal. The band is unsure about that, but then agrees. The band starts recording the first demo CD. Bella starts to worry because when they'll receive the deal, the band will release many records and go on tours. Bella worries also about her secret. The girls tell her that she can still keep her secret. The band finishes their demo CD and receives the deal, so they start recording their debut album. Meanwhile, Kelly and Bryan try to be a better couple, but nothing works.
Mysterious BookEdit Mysterious Book sectionEdit

Characters: Emma Gilbert, Cleo Sertori, Rikki Chadwick, Bella Hartley, Kelly Smith, Will Benjamin, Zane Bennett, Sophie Benjamin, Charlotte Watsford, Kim Sertori, Elliot Gilbert, Mr. Olsen

Plot: During a field trip, Cleo finds a mysterious book which appears to be magical. The girls decide to open it, but nothing works. When Will opens it with his own staff, something strange happens. The book releases a strange power which sucks Will inside the book. The girls are determined to discover the secrets of the book to free Will.

Note: Luke Mitchell temporarily leaves the cast to shoot a movie.
A RiddleEdit A Riddle sectionEdit

Characters: Emma Gilbert, Cleo Sertori, Rikki Chadwick, Bella Hartley, Kelly Smith, Zane Bennett, Charlotte Watsford, Kim Sertori, Don Sertori, Samantha Roberts-Sertori, The shop's owner

Plot: The book which trapped Will gives the girls a mystery: "A light in the vessel shines with the voice of the mermaids". While shopping with her family, Cleo is still determined to solve the mystery and the shop's owner hears the riddle's words. The owner tells Cleo that the words are from Thomas Lowitt's poem, "Mermaids". Cleo goes to the library and discovers the truth. Cleo figures out that Lowitt was a lighthouse keeper on an island called "The Mermaid Island". The poem titled "Mermaids" says that the island was put under the spell of a mermaid. Currently, the island doesn't exist, but its rocky parts still exist. Cleo knows everything and tells the girls that the book is the book of mermaid powers. The stone of the mermaid powers is on "The Mermaid Island" and the girls are determined to find it in hopes to release Will from the book.
The Mermaid Island, Part 1Edit The Mermaid Island, Part 1 sectionEdit

Characters: Emma Gilbert, Cleo Sertori, Rikki Chadwick, Bella Hartley, Kelly Smith, Lewis McCartney, Bryan Anderson, Zane Bennett, Sophie Benjamin, Charlotte Watsford, Kim Sertori, Don Sertori, Samantha Roberts-Sertori, Elliot Gilbert, Lisa Gilbert, Neil Gilbert, a boy, the nature photographer

Plot: The girls are planning the trip to The Mermaid Island to find a stone which can help release Will from the book. They lie to their families that they're going camping. Bryan stops Kelly for a minute and tells her that he didn't see her for such a long time. Bryan asks her why she's hiding from him, but Kelly says that she has something to do, which makes Bryan suspicious. The girls arrive at the island and discover that it is full of people although it is supposed to be deserted. The island's people seem to be looking familiar to the girls. The girls realize that it's an illusion. Emma accidentally takes a photo which shows a cave in the rocks.
The Mermaid Island, Part 2Edit The Mermaid Island, Part 2 sectionEdit

Characters: Emma Gilbert, Cleo Sertori, Rikki Chadwick, Bella Hartley, Kelly Smith, Bryan Anderson, Zane Bennett, Charlotte Watsford

Plot: The girls enter to the cave. Kelly starts to feel sick and stays behind with Cleo. Kelly then starts to get possessed by a mysterious illusion and she goes nuts, resulting in the rocks falling. Cleo's shoulder gets injured in the disaster. Kelly is again possessed by the illusion which makes her happy and search for a "light". Cleo finds the others and tells them about Kelly, Emma, Rikki and Bella, however, decide to find the stone first before looking for Kelly. However, the cave gets flooded. The girls realize that they can breathe and talk underwater. Emma, Rikki and Bella end up being possessed by the same illusion which got Kelly. The only one who isn't possessed is Cleo because of her injured shoulder. The girls find a lighthouse (with Kelly inside). Cleo discovers that all it just an illusion and uses all of her energy to stop it. But she awakens a monster which rises from the lighthouse. Meanwhile, back at the Gold Coast, Bryan is worried about Kelly and thinks that she has a secret which she's hiding from him.
The Mermaid Island, Part 3Edit The Mermaid Island, Part 3 sectionEdit

Characters: Emma Gilbert, Cleo Sertori, Rikki Chadwick, Bella Hartley, Kelly Smith, Bryan Anderson, Zane Bennett, Charlotte Watsford

Plot: The girls realize that all was just an illusion and they snap out of it. Cleo becomes weak and passes out because of losing all of her energy. Kelly gets captured by the monster. The girls try to fight with the monster, but they can't defeat him. Kelly is swallowed by the monster, but she gets out with a stone. The monster and illusion disappear and the girls realize that they can't breathe and talk underwater with the illusion gone. The girls use their magic to get back to surface. Cleo wakes up and the girls tell her about the monster. The girls call Kelly "a hero" because she defeated the monster by herself and found the stone. The girls return home and put the stone on the book. Nothing happens and the book gives the girls an answer: The book will open during a night of a full moon.
Secret InvestigationsEdit Secret Investigations sectionEdit

Characters: Emma Gilbert, Cleo Sertori, Rikki Chadwick, Bella Hartley, Kelly Smith, Will Benjamin, Bryan Anderson, Zane Bennett, Sophie Benjamin, Charlotte Watsford, Kim Sertori, Gracie Watsford, Julia Dove, Fred Smith, Agent Maria Medina, Agent Joel McTienan

Plot: Having forgotten about the book, Sophie calls the police to find Will. The girls are angry at her. Meanwhile, when the moon rises early, the book gives the girls the new powers: Emma can use telekinesis, Cleo can heal the injuries, Rikki can become invisible, Bella can use telepathy and Kelly can enter to the minds of other people. Kelly's father, who is a police officer, finds out that Will has a friendship with the girls and interrogates Kelly about his whereabouts. Kelly lies that Will is on vacation. Kelly's father hires two agents, Maria Medina and Joel McTienan, to interrogate the rest of the girls about Will's whereabouts. The girls use the same lie to keep the police from discovering their secret. Gracie and Julia find out about this and use that to expose the girls' secret. Gracie and Julia pretend to be innocent girls and tell the police that the girls are pretending to be Will's friends, but they actually hate him. This leads Kelly's father to interrogate her more. The girls find out that Gracie and Julia are standing behind this. While the rest of the girls fight, Kelly tries to distract her father and the agents from discovering the truth. During the battle, the book opens and releases Will. The girls' crystals gain more powerful power and merge into a jewel. However, Gracie and Julia steal the jewel and escape. Kelly uses her new powers to lure the police to the airport where they find Will who "has returned from vacation". Kelly's father is confused and apologizes to Kelly for being so mean to her. However, Kelly has a big problem: Bryan has seen the battle for a short time.
Another Secret RevealedEdit Another Secret Revealed sectionEdit

Characters: Emma Gilbert, Cleo Sertori, Rikki Chadwick, Bella Hartley, Kelly Smith, Will Benjamin, Bryan Anderson, Charlotte Watsford, Irene Smith

Plot: Bryan wants Kelly to tell him why she has big secrets that she's hiding from him. Emma and Rikki warn her to stay away from him. Kelly is unsure what to do. Bryan takes Kelly to the beach, but accidentally puts water on her. Kelly runs away, giving Bryan more suspicions. Bryan invites Kelly to his house and spills some water on her. Kelly jumps to Bryan's pool to hide, but he follows her and discovers her secret. Bryan is angry at Kelly for hiding from him that she's a mermaid and refuses to talk with her anymore.
Will He Accept the Secret?Edit Will He Accept the Secret? sectionEdit

Characters: Emma Gilbert, Cleo Sertori, Rikki Chadwick, Bella Hartley, Kelly Smith, Will Benjamin, Bryan Anderson, Zane Bennett, Sophie Benjamin, Nate, Kim Sertori, Don Sertori, Samantha Roberts-Sertori, Terry Chadwick, Mrs. Pitts, William Anderson, Lilly Anderson, Chucky Anderson

Plot: The girls find out that Bryan knows Kelly's secret. Kelly discovers that Bryan doesn't care about keeping her secret and fears that he will tell everyone. The girls tell Kelly to keep an eye on him. Bryan's parents invite Kelly for dinner and she finds out that Bryan wants to tell something. Kelly fears that Bryan will tell her secret. Bryan's annoying little brother hits Kelly with the water bomb and Bryan tells her to run. Kelly jumps to the water and thanks Bryan for helping her. Bryan tells Kelly that he will keep her secret and she tells him that Cleo, Emma, Rikki and Bella are also mermaids. Meanwhile, Cleo and Emma fight over who will keep Bucky, their pet rat. Rikki keeps Bucky until Cleo and Emma start to get along. Bucky makes a lot of mess at Rikki's house and her father wants the rat out. Cleo and Emma manage to get along and Rikki gives Bucky to Bella.
A Disagreement in Mermaid ClubEdit A Disagreement in Mermaid Club sectionEdit

Characters: Emma Gilbert, Cleo Sertori, Rikki Chadwick, Bella Hartley, Kelly Smith, Will Benjamin, Bryan Anderson, Zane Bennett, Sophie Benjamin, Charlotte Watsford, Kim Sertori, Fred Smith

Plot: Bryan now knows the girls' secret and wants to be the girls' second guardian. This results in him having a fight with Will. The girls try to comfort them, but nothing works. Bryan lets Will protect the girls, but agrees to be trusted to the girls.
Never Alone, Ever Again Never Alone, Ever Again section

Characters: Emma Gilbert, Cleo Sertori, Rikki Chadwick, Bella Hartley, Kelly Smith, Lewis McCartney, Will Benjamin, Bryan Anderson, Zane Bennett, Sophie Benjamin, Charlotte Watsford, Nate, Ash Dove, Kim Sertori, Don Sertori, Samantha Roberts-Sertori, Elliot Gilbert, Lisa Gilbert, Neil Gilbert, Fred Smith, Irene Smith

Plot: The girls begin to hardly ever stay together. Cleo is too busy with Lewis' visit to be with the girls. Emma is too busy with Ash's visit to be with the girls. Rikki is too busy at the cafe to be with the girls. Bella is too busy with recording the debut album with her band to be with the girls. Kelly is too busy with her relationship with Bryan to be with the girls. The girls realize that if they'll be away from each, their secret will be exposed and decide to stay together more.
MemoriesEdit Memories sectionEdit

Characters: Emma Gilbert, Cleo Sertori, Rikki Chadwick, Bella Hartley, Kelly Smith, Will Benjamin, Gracie Watsford, Julia Dove

Plot: Another full moon is approaching. The girls are unsure how to defeat Gracie and Julia with the jewel in their hands. The girls reminisce their old adventures as mermaids and decide to stop Gracie and Julia even if they don't have the jewel.
Is It the End for the Mermaids?Edit Is It the End for the Mermaids? sectionEdit

Characters: Emma Gilbert, Cleo Sertori, Rikki Chadwick, Bella Hartley, Kelly Smith, Lewis McCartney, Will Benjamin, Bryan Anderson, Zane Bennett, Sophie Benjamin, Charlotte Watsford, Nate, Ash Dove, Gracie Watsford, Julia Dove, Louise Chatham, Max Hamilton

Plot: The full moon is getting close. Lewis and Ash return to help the girls. With the jewel in their hands, Gracie and Julia are more powerful. Gracie and Julia trap the girls and their allies inside the jewel and take them to the moon pool. Gracie and Julia release the girls to steal their powers. The girls start a fight with Gracie and Julia, but are thrown to the moon pool. Miss Chatham and Max remind to the girls that they transformed into their powers during a battle with Gracie and Julia in their dreams. The girls touch their powers and transform to them. The girls are more powerful and throw the jewel out of Gracie and Julia's hands, crashing it. The girls defeat Gracie and Julia. With the jewel destroyed, the girls' allies escape. Gracie and Julia have become the good persons after the battle and apologize for being so mean. However, the girls have lost their humanity. However, through Lewis, Will, Zane, Bryan and Ash's efforts, the girls return their humanity and are again the ordinary girls. The battle resulted the girls in sacrificing their powers and causing Mako Island's magic to be gone again. Gracie and Julia can stay with Charlotte, Miss Chatham and Max. The girls return to their normal lives and Bella and her band release their debut album. Everything came back to normal.

Source - link

I HOPE THIS IS REAL ! ! ! ! ! :D