H2O: Just Add Water

Rikki and Cleo face their final year of high school without Emma.

Bella tries to keep Will away from the Moon Pool; the Moon Pool has changed.

Cleo wants to be an assistant dolphin trainer; Rikki fires Nate's band.

Cleo puts Lewis' Valentine's plans on hold; Don dates a woman named Samantha.

Zane promotes the café with a dirt bike race.

Bella tries to start a relationship with Will, but sees that he's got another girl; Lewis tests the magic water at school and attracts the attention of the science teacher.

A picnic leads Don to end his relationship with Samantha until Cleo encourages him to pursue it; Sophie competes with Bella for a job and sets her sights on Zane.

Rikki and Bella hide out at Cleo's to protect themselves from a full moon water attack; Bella is kidnapped by a water tentacle; Lewis tries to keep Will away.

Cleo experiments with the magic Moon Pool water; Rikki accidentally gets the water into Cleo's aquarium.

Will discovers that Bella is a mermaid.

Will is more interested in Bella as a mermaid than as a person.

Rikki receives counterfeit money at the café and is held captive by criminals on a boat; Bella and Cleo are forced to reveal the trio's secret to Will so they can rescue Rikki together.

Kim tries to derail Don and Samantha's wedding; Lewis receives an opportunity to study in America; Cleo realizes she's got to let Lewis live his own life and let him go overseas.

Zane challenges Will's free-diving skills; a unique crystal is found in the Moon Pool.

Sophie steals Bella's fundraiser idea; Samantha moves in.

Rikki is frustrated by the water attacks and goes to Mako Island on a full moon to confront the strange force in the Moon Pool; with Cleo and Bella delayed, Will pursues her and discovers she's been affected by the experience.

Cleo's introduced to Ryan, a young geophysicist who's working for Samantha; Rikki doesn't react well to Cleo consulting Ryan about the Mako rock and a fracture begins to appear in the trio.

Rikki fears Ryan will find out their secret when he begins spending more time on Mako Island.

Will gives up free-diving; Sophie kisses Zane.

Sophie becomes manager of the café; Bella can't stop sneezing.

Zane steals a Mako crystal to get Rikki's attention.

The girls take their final exams; the water force attacks early.

Bella wants to ask Will to the end of the year beach party, but thinks he has asked Rikki instead.

Cleo's dad gets a second job; Bella and Will try to find similar interests.

A comet is causing fish to flee from Mako Island.

The Moon Pool is damaged after the crystals have been harvested; a comet heads for Earth.