Falling Skies (9pm, TNT) - In the two-part season finale, a mission to destroy the Espheni power core turns complicated when Lexi returns. Later, Tom and Lexi must triumph over Tom's mortal enemy as they desperately try to destroy the all-powerful Espheni power core.
Secrets of Her Majesty’s Secret Service (8pm, UNC-TV) - The story of the British foreign-intelligence agency popularly known as MI6, which was created in 1909, featuring remakes from one of its former chiefs, an ex-spy and Bletchley Park codebreaker Mavis Batey.
MDA Show of Strength Telethon (9pm, ABC) - The 49th annual fundraiser benefiting Muscular Distrophy Association features performances by Rascal Flatts, Aloe Blacc, Matt Nathanson and others.
Manhattan (10pm, WGN) - Frank seeks medical answers, and Charlie and Helen travel to survey an off-site reactor.
Masters of Sex (10pm, Showtime) - Masters privately treats a couple for infertility and Johnson gets in over her head when she tries to treat Barbara Sanderson on her own. Also, Libby witnesses a hate crime (something she knows a thing or two about) that is whitewashed by the police.