A mermaid/man story with an evil twist including the dolan twins

Grayson Dolan has a problem. Ethan Dolan is kinda, sorta, maybe the cause of that problem. The solution to that problem? Break into the school. The only way they can go through with said solution? Invite a girl Grayson can't stand and Ethan borderline despises. But she's the best bet they've got.