Emma decides that she is not going to have her annual sleepover party due to what has happened to them. But Rikki and Cleo try to convince her otherwise. Meanwhile, Lewis conducts experiments on the girls.

Miss Chatham gives Cleo a warning that she doesn't quite understand. Until Emma finds herself in a trance and unable to change back from a mermaid under a full moon.

The full moon gives Cleo a power to put guys in a 'trance' and she suddenly gets a rush of admirers.

Emma invites Miss Chathams to stay at her place and Zane overhears Miss Chathams concerning about 'her treasure'.

Dr. Denman sets up a trap for the girls at Mako Island and Zane is forced to decide who he should be helping.