The Simpsons wake up to find that they have been robbed. In fact, all of Springfield has been hit by a cat burglar. The police are useless at stopping the robberies, so the townpeople start a Neighborhood Watch scheme, with Homer as leader. However, they end up causing more crimes that they were preventing.
Homer appears on "Smartline", where the cat burglar phones in and reveals that he will be stealing the world's largest cubic zirconia from the Springfield Museum. Homer vows to guard the museum, however, he gets drunk and the zirconia is stolen.
The townpeople are mad at Homer, until his father reveals he knows who the burglar is - Malloy, an old man at his retirement home. Malloy is imprisoned, and tells Homer that he hid his treasure under a "big T."
The whole town races off on a wild goose chase to find it, however, all they find is a note from Malloy saying there is no treasure after all, and he has escaped from jail. The townpeople keep on digging though...