TONIGHT'S MUST-SEES

"Lost" season opener, 8 p.m., ABC; preceded by series overview at 7. For most of its first four seasons, "Lost" only skirted the edge of fantasy. Then, as last season was ending, Ben "moved" the island. Did it go to another place? To another time? We start to get answers tonight, in an episode that's both weird and compelling. Jack and Ben are fierce enemies, but they agree on one thing: The Oceanic Six — the people who escaped the island — must return to set things right; also, they must bring Locke's body. That won't be easy. Kate and Sun won't budge. Hurley (Hugo) and Sayid are way too busy running from the police. And besides, how do you find an island that disappeared? Back on the island — wherever it is — things are more chaotic than ever. There are bizarre and bewildering developments, but "Lost" remains bracing, visually and emotionally. And with only two seasons (each 17 episodes) left, its story is starting to come together.

"Lie to Me" debut, 8:03 p.m., Fox. In real life, a professor has spent decades studying the tiny movements that signal a lie. Now this series imagines that two such experts (Tim Roth, Kelli Williams) have a private, truth-finding agency. This central gimmick will fascinate viewers, as tiny twitches reveal big things. Still, "Lie to Me" works mainly because it has smart stories. Tonight, a high school teacher has been killed, and one of her students is the prime suspect; also, a congressman is making weekly visits to a brothel. Each story has clever twists and surprises.

OF NOTE

Make 'em Laugh," 8 p.m., PBS. Even before movies had sound, people knew how to get big laughs; tonight's first hour looks at the art of physical comedy, from Charlie Chaplin to Jerry Lewis, Lucille Ball and beyond. The second hour is mostly verbal, viewing "groundbreakers." Some (Richard Pryor, George Carlin) eventually found a mass audience; others (Lenny Bruce, for instance) didn't. The mid-section of a three-week series, these hours provide a fun overview.

"American Idol," 7 p.m., Fox. Here's another one-hour audition episode, leading into "Lie to Me."

"The New Adventures of Old Christine," 7 p.m., CBS. As her wedding nears, new Christine learns she has a wild side.

"Criminal Minds," 8 p.m., CBS. Police suspect that family members combined on a kidnapping.

"Damages," 8 p.m., FX. Daniel Purcell (William Hurt) is starting to mirror the intriguing person played by Russell Crowe in "The Insider." Purcell is a scientist, with damning information about the company that employed him; under his cautious exterior is a scary intensity. Tonight, we learn more about him — and especially about his past with Patti Hewes (Glenn Close). Two gifted actors collide in a strong story.

"Vanguard," 5 and 8 p.m., Current (Oceanic Digital Channel 900). This satellite and cable channel (also available on www.current.com) usually has short reports, but "Vanguard" offers room for longer looks. Scheduled tonight is Adrian Baschuk's report on the Guantanamo Bay detention camps. He talks to the admiral in charge, plus guards, psych workers and a former detainee.