Cleo and Rikki face their final year of high school without Emma. They make a new friend in Bella and meet new boy Will – and encounter a strange new force on Mako Island that turns water against them.
Cleo's forced to put Lewis' plans for romance on hold to restrain Kim's out of control love life. During this Don meets Samantha, a National Parks Manager and they start to date.
Rikki receives counterfeit money at the cafe 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.
Zane concocts a dirt bike race to publicise the cafe. When Rikki discovers it's a scam she and Bella decide to teach him and Nate a lesson. Cleo and Lewis make a big discovery about mixing the waters in the Moon Pool.
Bella attempts to start a relationship with Will until she sees he's apparently got another girl. Lewis tests the magic Moon Pool water at school and attracts the attention of their Science teacher.
