Walter Hendrix III

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.

In the season finale, Founder's Day has finally arrived, and everyone is busy with last-minute preparations for floats and fireworks. Stefan is uncomfortable with Damon's new attitude toward Elena, but Elena is more concerned about repairing her relationship with Jeremy. Jeremy is worried about Anna (recurring guest star Malese Jow), but not sure he's on board with her latest plan for the future. While Caroline is enjoying her day as queen of the celebration, she also tries to help Matt and Tyler get their friendship back on track. Finally, although Damon and Alaric do their best to stop him, John Gilbert (recurring guest star David Anders) sets a plan in motion that brings Founder's Day to an end amid chaos, destruction and death.