After her well-to-do Aunt Sarah is caught shoplifting, Virginia Trent is convinced she needs to seek psychiatric help for kleptomania. So why does Virginia turn to legal eagle Perry Mason? Because a cache of valuable diamonds—left in Sarah's care—has suddenly vanished into thin air.

Virginia thinks Sarah swiped the stones, but gem dealer Austin Cullens begs to differ. In fact, he's prepared to forgive and forget—until he is mysteriously murdered and Sarah is caught running from the crime scene. Now it appears the lady with the sticky fingers may have blood on her hands.