Chlorine

Alice caused an accident that made Ryder had to step down the swimming competition. Ryder hated Alice's guts and the feeling was mutual. She couldn't swim because she had always been afraid of the depth because of an accident when she was a child. Gustav, a fratboy, a swimming athlete wanted to help Alice to overcome her fear. She liked him because he's charming and refreshing. He liked being with her because she's nice and friendly enough to help him asking her sister out. Anita always had her way to charm Alice's crushes and eventually dated them. It sucked when your shared the same love interest with your sister.

Frat boys are bad news and not good for your heart.