Something strange is going on in Missy Barrett's neighborhood. Someone is stealing things from people on her block and replacing them with strange items. It all began when one of Mrs. Whittington's knitting needles went missing and a sewing thimble was left in its place. Now everyone is noticing things disappearing from their homes, and it's up to Missy Barrett to solve the mystery of "The Case of the Thoughtful Thief."