Here's a look at tonight's sci-fi TV:
Lost, 'What They Died For' – The focus returns to the main castmembers as FLocke plans a new strategy to leave the island and Jack's crew hunts for Desmond. A few departed castmembers will also return in tonight's ep, the final one before the giant-sized series finale. (9 p.m. ET on ABC)
V, 'Red Sky' – The season one finale of V is here! Erica boards the V mothership in an attempt to destroy Anna's soldier eggs. Elsewhere, Chad discovers that Anna has been manipulating him, and Val is stalked by a stranger as she's about to give birth to her baby (10 p.m. ET on ABC)
Head after the jump for preview clips.