As the Season Finale, Zack's records were sent out the window when he participated in a fight with Vernon, and Zack lost his entire memory. Zack's friends must retrieve the Zack Files and tell him all of the most important Zack Files to give Zack a chance to retain all his memory. Clips of previous episodes in Season One and Season Two were viewed in attempt to get Zack to become himself again, and once he saw his record files that Vernon had retrieved to announce to Zack that he was one of Vernon's minions, his memory was restored. (thetvdb.com)