TONIGHT'S MUST-SEE

"Nashville," 8 p.m., Fox. Last week brought a warm introduction to some country-music hopefuls. Brief samplings indicated that Chuck Wicks and Mika Combs have terrific voices. Several others didn't sing a note. Now we'll hear some of them. Sarah Gunsolus, Rachel Bradshaw and Lindsey Hager have formed a trio. Tonight, they audition for a talent scout. Meanwhile, the radiant Combs, a coal-miner's daughter, fresh from Kentucky, complicates things.

"Doctor Who," 10 p.m., SciFi. Before the "Torchwood" series began, the Captain Jack character was created on "Doctor Who." Here's one of the episodes, the start of a three-parter involving cannibals.

OF NOTE

"Ghost Whisperer," 7 p.m., CBS. Melinda has ominous messages from the ghost prophet.

"Las Vegas," 8 p.m., NBC. Sam is missing and Mike starts a desperate search. Also, Ed gets an ultimatum from his wife, and Mary has acted strangely since her dad got out of jail.

"The Unit," 8 p.m., CBS. The entire unit is being investigated for possible war crimes. For now, there won't be any military duty.

"Numb3rs," 9 p.m., CBS. A mystery man seems to have a list of spies and double agents. He works in code and Charlie tries desperately to do some deciphering.

"Law & Order: Special Victims Unit," 9 p.m., NBC. Fin's son asks him to investigate a rape in a college dorm. He works with Chester Lake (Adam Beach), the American Indian detective who will be an "SVU" regular this fall.