Riff's little sister, Cass, was one of the so called founders of the Jets. When Riff and Tony came up with the Jets, Cass insisted on joining and they let her after some convincing. Once Tony was taken away it was just Riff and Cass and the Jets. Riff was always protective of his little sister weather it was on of the guys from the Sharks hitting on her to one of his own Jets. So when Baby John catches feelings for her he has to hide them until Cass reveals her feelings for the boy. Riff doesn't want Cass to date anyone so this causes Baby John and Cass to secretly date. Can they hide it from Riff long enough while the rest of the Jets are worried about Tony and Maria and the sharks?