Is there a thief at Sweet Valley Middle School?  Things have started disappearing, and the whole school is searching for the culprit.  But everyone is shocked when some of the stolen goods turn up in Jessica Wakefield's locker! Jessica insists that she's been framed, but the only one who believes her is her twin sister, Elizabeth.  When Jessica and Elizabeth team up to catch the real thief, they can hardly believe what they find out!