* Lost (9/8c ABC)
Did the Locke monster really get rid of Desmond? And did L.A. Desmond really get rid of L.A. Locke? You won't get an answer here, but we will note that Henry Ian Cusick isn't listed in the guest cast for this episode, which finds the Locke monster's camp (Sawyer, Kate, Sayid) merging with Jack's group (formerly Ilana's, including Hurley, Sun, Alpert, Ben etc.). The merger won't be seamless. In L.A., meanwhile, the focus is on Jack. Finally, a programming note: A rerun (the Alpert episode, "Ab Aeterno") is scheduled for next week - to give you a breather before the final four.
* Glee (8:59/7:59c Fox)
Madonna doesn't show up in person, but her music - and her attitude - are all over this episode. Of course, you could say that Madonna's attitude infuses every episode that Sue's in (and she's in all of them), and in fact, McKinley High's most hiss-able villain gets a Madonna makeover tonight, courtesy of Mercedes and Kurt. The Material Girl's material is tied primarily to a story line about female empowerment, but "Like a Virgin," has a special resonance for several of the characters.
* Dancing with the Stars (8/7c ABC)
Last night the stars brought to mind stories of Hollywood glitz and glamour as they danced to songs from movies. But tonight's exiting star will get a reminder that not all movies have happy endings. We don't know who narrowly escaped elimination last week because Tom specified that though Niecy and Louis had to wait until the end to hear their fates, they weren't necessarily in the bottom two. That means the field is wide open for guessing who will go home.
Semi-regulars pop in and out of this show after indeterminate absences, just as folks do in real life. Remember Raylan's old neo-Nazi frenemy Boyd Crowder (Walton Goggins)? He had found the Lord in his hospital bed after Raylan had shot him, and we'll now see how Boyd's body and soul are holding up. Meanwhile, Raylan's getting hit on again, this time by the widow of a horse breeder whose missing art collection he's trying to track down. Robert Picardo, Katherine LaNasa and Brett Cullen are in the guest cast.
* The Biggest Loser: Couples (8/7c NBC)
Volleyball star Gabrielle Reece hits the beach with the players tonight, leading them through a rigorous seaside workout. But first, the contestants face a special challenge when they learn the kitchen on the ranch is closed for the day. Instead of eating specially prepared cuisine, they must choose meals from a buffet featuring food with both high and low calories. But the task becomes more complicated when they learn that whoever eats the most calories wins the sole vote at elimination.