TONIGHT'S MUST-SEE

"Prison Break" return, 7 p.m., Fox. The first half of the season rippled with energy and desperation then left us hanging. Lincoln has been framed for a murder he didn't commit — and maybe nobody committed. His half-brother, Michael, developed a great escape theme. Then Michael found that a change in the prison design makes that impossible. On the eve of the execution, things are desperate. On the outside, Lincoln's lawyer talked too much to a TV reporter. Then she saw the aftershock: One FBI agent killed another just to keep the frame-up secret.

"The New Adventures of Old Christine," 8:30 p.m., CBS. Last week we met Christine (Julia Louis-Dreyfus), whose ex-husband has a new girlfriend who also is named Christine. Tonight, she tries to do something about her vacant love life. That leads to some funny blind dates and to a possible soul mate (Matt Letscher).

OF NOTE

"Related," 7 and 8 p.m., WB. This excellent series has been mishandled by WB and isn't likely to be back. Still, catch the season's final two hours: Marjee, the wild sister, is ready to have her boyfriend move in. Rose, the calm one, gets drunk and gets more assertive about romance. Ginnie, the authoritative one, tries to mend her marriage. In the second hour, the sisters reminisce about their late mother (Dana Delany).

"How I Met Your Mother," 7:30 p.m., CBS. Marshall is an intern at Barney's business — and soon feels the place is making him shallow.

"Two and a Half Men," 8 p.m., CBS. Alan was kind of happy about having a young girlfriend. Now he has trouble, though: She needs help paying her bills.

"24," 8 p.m., Fox. The terrorists are preparing an even nastier attack, unless Jack can quickly do something.