 Living together begins to take its toll on Kelly and Brandon s relationship. Donna asks David to move back in with her at the beach front apartment, but with a stipulation that they sleep in separate rooms and that he doesn t tell her parents. Meanwhile, Steve has a couple of run-ins with Carly Reynolds, a young, overprotective, sarcastic, single mother with a six-year-old boy, named Zack, whom Steve becomes interested in knowing more about.