Xander gets a text from Chris but when they call the number it goes to voicemail to some doctor. They use the internet to find where she is and wait outside her house. They track her to the base and drive away when they are caught but now they know where Chris must be. 

Ben and Maddie go to visit Ryn who still wants them to help her find her sister. They promise they will but first they want to talk to her and learn more about who she is. She explains that in the water you kill or are killed. She also reveals that there are many other mermaids, not just her and her sister.

They then use a primate intelligence test on Ryn which she completes right away. 

During one of these tests Ryn almost kisses Ben who gets lost in her. They get distracted with a call and Ryn ends up following their friend Jerry to a party. There Ryn ends up falling in the pool but doesn't transform because it isn't ocean water. She tells Maddie that the man in the car was going to hurt her. 

Ben's brother asks him at the party if he would work with him and their dad. Ben isn't a fan of the idea 

Maddie's dad starts to connect some clues as he investigates the death of the man Ryn killed. 

In the lab they begin to test Ryn's sister and her DNA on rats.