TODAY'S MUST-SEE

"Little Girl Lost: The Delimar Vera Story" 6 p.m., Lifetime Movie Network. People grew weary of Luz Cuevas' obsession, this film says. She insisted her baby hadn't died in a fire; a kidnapper came as the blaze began. Luz was dismissed by officials, divorced by her husband. Then, six years later ... well, this is one you should see. Based on a true story, it's one of the best TV movies in years. Paul Kaufman has directed a superb cast, led by Judy Reyes ("Scrubs") as Luz, Hector Bustamante as her husband and Ana Ortiz ("Ugly Betty") as his distant cousin.

Olympics, 6 p.m. and daytime, NBC. Swimming has ended and track is here. The 100-yard-dash winner tonight will be called the world's fastest woman. Also tonight: finals in individual gymnastic events and women's springboard diving. Plus, the U.S.-Poland women's volleyball game. Coverage continues with beach volleyball, track cycling, badminton, 10,000-meter run and more.

OF NOTE

"Noah's Ark" (1999), 5 p.m., ION. This miniseries has a bright look, a good cast (Jon Voight, Mary Steenburgen, etc.) and odd touches. After the flood, Noah even confronts merchants and a pirate ship.

"The Simpsons," 8 p.m., Fox. We flash back to when Marge was smitten with someone else; a despondent Homer invented grunge music.

"Masterpiece: Inspector Lynley Mysteries: Know Thine Enemy," 8 p.m. PBS. This is considered the last new "Lynley" mystery, shortly after the last new "Foyle's War." So it's appropriate that Honeysuckle Weeks (who played Samantha, Foyle's driver) has a splashy guest role. In a complex kidnapping story, Lynley and Havers (Nathaniel Parker and Sharon Small) disagree on whether she's a culprit or a victim.

"Mad Men," 7 p.m., AMC. This season started with Valentine's Day, 1962. Now it reaches Easter, in a subtly crafted episode. Peggy is advising the new priest on sermon-writing. The entire staff, having dumped its small-airline account, prepares for a Good Friday pitch for one of the big airlines.