S1, E21: Isobel (recurring guest star Mia Kirshner – The L Word, 24) returns to town and stuns Alaric with her attitude and her demands that he arrange a meeting with Elena. When mother and daughter finally meet, Isobel refuses to answer most of Elena's questions, but reveals that she will stop at nothing to find the mysterious invention John Gilbert has been searching for. Isobel's dangerous actions lead Stefan, Damon and Bonnie to step in and help Elena deal with the situation.