TONIGHT'S MUST-SEE

"The Unit," 8 p.m., CBS. This series has become a quick ratings hit and here's an example of why. A clever script offers surprises on three different stories. Bob (Scott Foley) is supposed to protect the secretary of state during a surprise visit to Africa. That won't be easy because there are some jolting schemes going on. Back home, his wife Kim (Audrey Marie Anderson) works at the radio station. That's where a crisis arrives. Meanwhile, Molly (Regina Taylor) helps someone and confronts an investment opportunity. Keep an eye on this. A tough military show on the surface, "The Unit" offers interesting detours.

"Monk," 9 p.m., USA Network. After all these years of being a consultant to the police, Adrian Monk takes a fresh step. Following Natalie's advice, he opens a detective agency. His first client (Sharon Lawrence) seems to have a simple task for him. Since this is Monk, it soon escalates.

OF NOTE

"Windtalkers" (2002), 5 p.m., A&E. John Woo directed this film, which has Windward O'ahu doubling for Pacific wartime locations. It mixes World War II action with one of the war's fascinating stories: To beat codebusters, the U.S. simply had Navajo soldiers talk in their native language. Nicolas Cage stars.

"Commando" (1985), 5 p.m., AMC. This is a classic-style Arnold Schwarzenegger film — sharp, direct, well-filmed and occasionally funny. Schwarzenegger is out to rescue his daughter (Alyssa Milano); Rae Dawn Chong co-stars.

"Stargate SG-1," 6 p.m., Sci Fi Channel. Ba'al says he can direct the team to an important ancient weapon — but only after he gets help battling his clones.

"NCIS," 7 p.m., CBS. This rerun goes back to the end of the previous season. A sniper is loose and may be Gibbs' nemesis, Ari.

"The Science of Shark Sex," 7 p.m., Discovery Channel. Is this what they meant when they said there would be a lot of sex on cable? If we watch the mating habits of sharks, do we still have to pay our cable bill?

"Las Vegas," 8 p.m., NBC. Jaime Pressly ("My Name is Earl") guests, as someone who shows up to thank Ed (James Caan) for saving her dad. Meanwhile, someone finds part of a finger in the buffet. This is not what is meant by finger food.

"Numb3rs," 9 p.m., CBS. A federal agent reportedly committed suicide. Don, who once had a romance with her, has doubts.

"Law & Order," 9 p.m., NBC. A man is killed shortly after destroying a valued Torah.

"Psych," 10 p.m., USA Network. To keep up his claim of being a psychic, Shawn pretends to get messages from a cat.