"Ab Aeterno" is the ninth episode of season 6 and the 112th episode overall. The episode aired on March 23, 2010 in the United States. The episode focuses on Richard Alpert, who arrived on the Island as a prisoner on a slave ship. This episode does not feature a "flash-sideways". Almost the entire episode is set in Richard's flashback. It is the first episode of season 6 not to feature the alternate timeline.