1.06 - Lost Girls

Elena demands that Stefan explain the frightening events that have been happening in Mystic Falls. In a string of flashbacks, Stefan explains how his rivalry with Damon began back in the Civil War when they met the love of their lives Katherine, the vampire who was the one that sired both of them. In the present, Damon impulsively takes control of Vicki's future, and a confused and frightened Vicki runs away. Also, Sheriff Forbes, Mayor Lockwood, Logan and the others take drastic steps to protect their town.

Source: IMdb