* THE KILLING SEASON. 9 p.m. Saturday, A&E.

Eight-episode series produced by Alex Gibney (Going Clear) looks at unsolved slayings of sex workers in places that include Atlantic City, and at possible links to Long Island serial killer case.

* THIS IS LIFE WITH LISA LING. 10 p.m. Sunday, CNN. Ling rides with 22nd District Philadelphia police officers who were among the first here to wear body cameras.

* TUCKER CARLSON TONIGHT. 7 p.m. Monday, Fox News Channel. The former Fox & Friends Weekend host, who's also worked at CNN and MSNBC, launches a weeknight show.

* MARS. 9 p.m. Monday,

National Geographic Channel.

From Brian Grazer and Ron Howard (Apollo 13) comes a documentary-drama hybrid min-iseries about the first human mission to the red planet, inspired by Stephen Petranek's book How We'll Live on Mars.

* GOOD BEHAVIOR. 9 p.m.

Tuesday, TNT.

You'll never look at Downton Abbey's Lady Mary the same way again. Two-hour season premiere introduces Michelle Dockery as Letty, an ex-con who becomes entangled with a very dangerous man (Juan Diego Botto).

* UNDERCOVER. 8 p.m. Wednesday and Thursday, BBC America.

Two-night, six-hour mini-series stars Sophie Okonedo (Hotel Rwanda) as a British attorney trying to save the life of her death row client, unaware of a conspiracy back in London that involves her husband. The plot's beyond convoluted, but it's a crackling family drama.