S1, E4: Elena asks Stefan to escort her to the town's annual Founder's Party. Vicki gets Tyler to ask her to the party, and then accuses him of trying to hide their relationship from his family. Zach (recurring guest star Chris William Martin - "Heartland," "The L Word") reveals a useful family secret to Stefan. At the party, Damon tells Elena a story about the Salvatore family's past, leaving Elena with questions that Stefan refuses to answer. Finally, Stefan takes action to get Damon out of his life for good.