Monk goes undercover at a department store to investigate the mysterious death of a popular store employee. In the process he also gains valuable insights into the life of his former partner, who happens to be the store's head of security.

A woman commits suicide and minutes later Captain Stottlemeyer is shot nearby. Monk needs to determine if the two events are related, but his new medication has turned him into an obnoxious jerk who can't concentrate on the case.