In order to get through to Lily about Julian's manipulating ways, Stefan and Damon confront their mother with painful memories from their childhood. However, when Lily reveals a dark secret she's been harboring for over 160 years, Stefan and Damon are left questioning everything they've ever known about their family. Determined to prove himself to Lily, Enzo comes face-to-face with Julian and challenges him to a duel, but an unexpected twist threatens to complicate things. Elsewhere, Matt finds himself in the middle of a deepening mystery involving the residents of Mystic Falls, and Caroline's world is turned upside down when Valerie reveals some life-changing news to her.