After Shawn and Gus help a little girl get a mall Santa out of jail in time for Christmas, they realize their clients are con men who have a big score planned. Helping them with their investigation is Gus' sister Joy, in town for the holidays and looking to repeat a one time fling she had with Shawn, who is determined to keep his best friend from ever finding out. Phylicia Rashad and Keith David guest star as Mr. and Mrs. Guster, with John Landis directing the episode.