The Walking Dead — The monster hit returns for its third season and those gruesome ghouls are still in attack mode. Rick Grimes (Andrew Lincoln), now hardened and weary, continues to seek refuge with his fellow survivors in a desolate world, but the struggle to survive has never been more perilous. Season 3 also introduces new characters, including the maniacal Governor (David Morrissey) and the sword-wielding Michonne (Danai Gurira). 9 p.m. Sunday, AMC.
TODAY: Ever wonder what Scott Baio is up to? Wonder no more. The Happy Days star returns to prime time in See Dad Run, a comedy in which he plays a former TV dad adjusting to actual fatherhood. 8 p.m., Nickelodeon.
MONDAY: Turns out that Steve McGarrett’s (Alex O’Loughlin) mother (Christine Lahti) isn’t going away quietly on Hawaii Five-0. She pays his son a surprise visit as the team investigates the death of a polo player. 10 p.m., CBS.
TUESDAY: It’s Round 2 of the presidential debates as Barack Obama and Mitt Romney square off in a town-hall format. We can only hope that CNN’s Candy Crowley makes for a competent moderator. 9 p.m., broadcast networks and cable news channels.
TUESDAY: Emily Owens, M.D. is basically Grey’s Anatomy-lite. Mamie Gummer stars in the title role as a love-starved young doctor — and former nerd — who discovers that hospitals are a lot like high school. 9 p.m., The CW.
TUESDAY: The Men Who Built America is a series that explores how five powerful men — Cornelius Vanderbilt, John D. Rockefeller, Andrew Carnegie, J.P. Morgan, and Henry Ford — transformed the country into a global superpower. 9 p.m., History Channel.
WEDNESDAY: Mama drama on Suburgatory? In the Season 2 opener, Tessa (Jane Levy) begins to express an interest in her mom, who abandoned her when she was a baby, and George (Jeremy Sisto) suddenly feels threatened. 9:31 p.m., ABC.
WEDNESDAY: Brace yourself for another twisted, crazy and scary ride. American Horror Story: Asylum returns with an entirely different saga set inside a New England facility for the criminally insane. Jessica Lange is back — this time as a sadistic nun. 10 p.m., FX.
THURSDAY: Ethel is a compelling profile of Ethel Kennedy that spans the life she shared with husband Robert Kennedy and the years following his death. The film is directed and narrated by her daughter, Rory Kennedy. 9 p.m., HBO.
FRIDAY: Ding-dong, Percy is dead, but Nikita is still roiling with danger. Now in charge of Division, Nikita and Michael (Maggie Q, Shane West) are out to capture a group of rogue agents called the Dirty 30. 9 p.m., The CW.
SATURDAY: The Girl is a new film that delves into Alfred Hitchcock’s dark side. It follows the famed director (Toby Jones) as he develops an creepy obsession for Tippi Hedren (Sienna Miller), his leading lady in The Birds and Marnie. 9 p.m., HBO.