"KLAUS (GUEST STAR JOSEPH MORGAN, "BEN HUR") IS REVEALED --- Stefan (Paul Wesley) and Damon (Ian Somerhalder) are furious when they discover that Elena (Nina Dobrev) has defied them both to make a new ally and take control of the plan to out-maneuver Klaus (Morgan). Disagreement over how to protect Elena leads to growing tension between the Salvatore brothers. Meanwhile, Stefan has his hands full trying to keep a confused and frightened Jenna (Sara Canning) safe. Flashbacks to 1491 reveal Katherine's (Nina Dobrev) introduction to Elijah (Daniel Gillies) and Klaus, along with the origin of the moonstone curse. Elena learns shocking new information about Klaus' motives. Matt Davis also stars. Joshua Butler directed the episode written by Kevin Williamson & Julie Plec (#219)."
Source: TVDNEWS , Ksite