* NCIS (8 pm/ET CBS)
NCIS, which is a spin-off of JAG, may spin off a series of its own. Tonight's episode (the first of a two-parter) introduces characters, played by LL Cool J and Chris O'Donnell, who are rumored to be the leads of the series that could debut in the fall. They play undercover agents for NCIS's Office of Special Projects (OSP) in Los Angeles. In the episode, the murder of a marine sends Gibbs and McGee to L.A. to work with the OSP, and the case turns into a matter of national security.
* Dancing with the Stars (9 pm/ET ABC)
This is when it starts getting really hard to bid adieu to another contestant, because these celebs can see the finish line within their reach. Nevertheless, another star is going home tonight, and scores from last night's team dances will play a factor in that decision. Perhaps last week's casualty, LT, will help cushion the blow and invite this week's departing contestant to join him on the golf course. Also on the show: Robin Thicke performs, and the professional-dancer competition continues with four contestants.
When last we saw Jimmy Keefe, he was emphatically exiting Tommy's dream life. (Flames were involved, as you might recall.) Well, he's back tonight, but not in the way dead people usually are on this show, and that leaves Tommy more than a little haunted. Meanwhile, Mike's bar finally opens, following a chat with his mom. (She's dead, too, remember.) Ladder 62 guys pitch in to help (Franco's the bouncer), but Sean can't do much heavy lifting because his back just won't get better.
* Law & Order: Special Victims Unit (10 pm/ET NBC)
Gail O'Grady and Hilary Duff play mother and daughter in tonight's episode. (Too bad Faye Dunaway isn't on hand to play Duff's grandmother.) In trademark "ripped from the headlines" style, O'Grady's character reports the disappearance of her toddler granddaughter, but an Amber Alert proves unsuccessful. Detectives then begin to look closely at the toddler's irresponsible young mother (Duff), who soon becomes their prime suspect. Lizzie McGuire would be shocked, indeed.
* Life After People (10 pm/ET HISTORY)
Though most people tend to think of plants and animals as wild, the hand of man is continually in control both for good and bad, as they are cultivated and at times brought to the point of extinction. This second episode of the series theorizes about what would happen if man no longer played a role in the natural cycle, and flora and fauna were truly wild.