The show continued from February 9 at its new timeslot of Tuesdays at 9 pm , with a total of 18 episodes airing in 16 broadcasts , ending with a two and a half hour , two-part series finale , the latter part of which aired Sunday , May 23 , 2010 . The show continued from February 9 at its new timeslot of Tuesdays at 9 pm , with a total of 18 episodes airing in 16 broadcasts , ending with a two-and-a-half-hour , two-part series finale , the latter part of which aired Sunday , May 23 , 2010 .