Cory's mom wants him to try and be more polite. He's excited at first, when his politness lands him a cute new girl friend, TK. However, when she begins to come on too strong, he has second thoughts. When he tries to put on the brakes TK gets upset. Cory later finds out that TK stands for Theresa Keiner, as in Harley's sister! Harley insists that Cory keep his date with TK or face the consequences.
TK tries to kiss Cory. Uncomfortable, he backs off and tries to make conversation. When the topic switches to baseball he finds out that it's a sensitive topic for Theresa; her father abandoned her at a baseball game. Turned on by Cory's politeness and genuine interest, TK makes another move on Cory. This time Harley shows up and chases Cory away.
At school Harley starts in to punish Cory for taking advantage of his sister; but he becomes distraught when he discovers that it was TK that made the move. Cory assures Harley that all TK needs is a positive influence. Harley is comforted by this and expresses his desire to have TK date a sensitive, caring boy such as Cory.