TONIGHT'S MUST-SEE

"When the Levees Broke" conclusion, 6 p.m., HBO. The first half of Spike Lee's documentary concluded Monday with New Orleans under water and waiting for help. Some people had acted with immense heroism, rescuing their neighbors; others had looted. In this second half, the wait continues. Conditions at the Superdome and the Convention Center deteriorate. Federal, state and city officials respond sluggishly. There are shattering moments. Terence Blanchard — the trumpeter who composed the documentary's excellent score — takes his elderly mother home for the first time in months; she's deeply dismayed by the damage to her house. But there are also upbeat moments, especially when a military officer finally takes control of the efforts to help. "Levees" is beautifully crafted. Like a flood, its anger starts at a trickle, then grows to a great, rolling rage.

OF NOTE

"Concert for America's Kids," 7 p.m., CBS. Great singers perform, in a fundraiser to help latchkey kids. Performers include country's Martina McBride and Kenny Chesney, classical star Andrea Bocelli and rock-pop stars Bon Jovi, Mary J. Blige and Sting.

"House," 7 p.m., Fox. An angry patient strolls in and shoots Dr. House. Now the doctor is in intensive care, increasingly frustrated as a patient's diagnosis eludes him.

"Vanished," 8 p.m., Fox. If you missed Monday's terrific debut, catch this quick rerun. A senator's wife disappears at the party where she's being honored. By the end of the hour, we aren't sure what happened — or who she is. It's the start of a mystery that will unfold throughout the season.

"Law & Order: Special Victims Unit," 9 p.m., NBC. A school shooting seems to be racially motivated. Marcia Gay Harden and Cody Kasch ("Desperate Housewives") play people who have hate material.

"P.O.V.: Lomax the Songhunter," 10 p.m., PBS. At a time when few city people seemed to care, John Lomax traced the early greats of folk music. He got Leadbelly out of jail; he recorded Woody Guthrie. This documentary traces the life of his son, Alan, who continued the mission after World War II. It includes interviews with Pete Seeger, Jean Ritchie and other folk stars.