TODAY'S MUST-SEE

"Longford," 6 p.m., HBO. Here's a story that's slow and subtle with a deep sense of melancholy. It's the true story of the Earl of Longford (Jim Broadbent), who diligently visited prisoners. He befriended Myra Hindley (the gifted Samantha Morton), convicted in the UH's famous Moors murders case in the 1960s. There's a darkness here as a decent man gets into murky and confusing turf. The result is intelligent and dismaying.

"Special Investigations Unit: MLK — Words That Changed a Nation," 3, 6 and 9 a.m., CNN; same times tomorrow. The writings of Martin Luther King Jr. are stored at Morehouse College in Atlanta, offering rich insights into history. King was a wordsmith, says his former colleague, Andrew Young. We see that in his handwritten changes, always going for the more lyrical phrase. And we hear the story of his famous speech in Washington, D.C. The draft has no reference to dreams. Aides, who had heard that passage before, wanted him to skip it this time. King stuck to the text, then set the paper down and intoned, "I have a dream ... " He created a stirring moment in history.

OF NOTE

"Cast Away" (2000), 7 p.m., ABC. Much of this movie offers only one guy, stranded on an island, with no one to talk to except his soccer ball. Fortunately, the guy is played by Tom Hanks, skillfully directed by Robert Zemeckis. The result is thoroughly entertaining, despite a so-so ending.

"Law & Order: Special Victims Unit," 8 p.m., NBC. In a rerun, Fin looks into a rape case at the college where his son works.

"Save Our History: The Search for George Washington," 8 p.m., History Channel. This documentary traces a two-year effort to create exact likenesses of George Washington at ages 19, 45 and 57.

"Saturday Night Live," 10:30 p.m., NBC. Justin Timberlake doubles as host and musical guest on this rerun.