TONIGHT'S MUST-SEE

"Heroes," 7 p.m., and "Chuck," 8 p.m., NBC. Here are quick reruns of Monday's premieres — this time with "Heroes" airing first. Last year, "Heroes" proved that a fantasy show can have a bright look and light mood, even in deadly situations. That was copied by several shows this season — including "Chuck," but not including the dark and gloomy "Bionic Woman." As "Heroes" begins, a new killer is loose, Claire and her adoptive dad are trying to be unnoticed and Mexican twins with special powers are trying to cross the border. On "Chuck," a likable geek accidentally absorbs the nation's top secrets.

"Saturday Night Live" season opener, 10:30 p.m., NBC. Things are unchanged this year, which isn't so bad. There are 11 regulars, with Seth Meyers and Amy Poehler anchoring "Weekend Update." LeBron James hosts tonight with music from Kanye West.

OF NOTE

"Shrek" (2001), 5 p.m., TBS. Families might want to re-watch this animated delight.

"Back at the Barnyard" debut, 6 p.m., Nickelodeon. "Barnyard," an animated movie from 2006, has been transformed into a series. The opener has some good comedy moments, built around a dark theme: The animals are convinced the farmer has given up his vegetarianism and is ready to eat them.

"Species: The Awakening," 6 p.m., Sci Fi. We meet approximately the most beautiful professor in human history. (She's played by Helena Mattsson, a Swedish native in her first major role.) Like many beauties, perhaps, she sometimes transforms into a repulsive and deadly creature. Her guardian (Ben Cross) tries to help, in a standard horror film, with occasional thrills.

"Cops: 20 Years ... Caught on Tape," 7 p.m., Fox. The show pauses to replay some of its strangest moments so far.

"Moonlight," 7 p.m., CBS. Here's an instant rerun of the show that made its debut at 9 p.m. Friday. It's a subtly shaded drama, well-cast with Alex O'Loughlin as a vampire private eye and Sophia Myles as a reporter.

"Cane," 8 p.m., CBS. Here's a rerun of Tuesday's debut, with Jimmy Smits at the center of a so-so soap opera about a family and its sugar-cane business.