After Mr. Belding accidentally bumps into Zack before a big basketball game and injures his knee, he gets rushed to the hospital and gets told by Lisa's mother that he has to have surgery to repair the damage. As a result, Zack gets scared and tries to sneak out before going under the knife.

After Screech makes it to the all city chess finals, Zack and Slater make a bet with Valley that he will win, which soon leads to trouble.