FLASHBACKS TO NADIA’S SEARCH FOR KATHERINE — While Nadia (guest star Olga Fonda) remembers her centuries-long search for her mother, Stefan (Paul Wesley), Caroline (Candice Accola) and Matt (Zach Roerig) come up with a desperate new plan to save Elena’s (Nina Dobrev) life. For the second time, Bonnie (Kat Graham) and Jeremy (Steven R. McQueen) must turn to Liv (guest star Penelope Mitchell) for help. Damon baits Tyler (Michael Trevino) into a nasty confrontation, then takes off to seek revenge on Dr. Wes (guest star Rick Cosnett). Caroline and Tyler come to a new understanding. Finally, Bonnie learns of a terrifying secret that will threaten the lives of all her friends. Lance Anderson directed the episode written by Melinda Hsu Taylor (#515).