‘Mad Men’ back for season three

The long-awaited return of TV’s smartest, most stylish and best-written series is over.

“Mad Men” (10 p.m., Sunday, AMC, TV-14) returns for a third season of drinking, lying, philandering, office-scheming and the kinds of weird surprises and misunderstandings that erupt when characters live behind layers of masks and illusion.

As the season begins, the staff of the Sterling Cooper advertising agency is just getting used to their new British partners .

Don Draper (Jon Hamm) awaits the birth of his third child and muses on his own arrival in the world, offering us a chance to discover more about the many secrets and lies behind his original identity and complete reinvention.

Tonight’s highlights

Olympic hopefuls compete in women’s gymnastics (8 p.m., NBC).

The voices of Will Smith, Jack Black and Robert De Niro animate “Shark Tale” (8 p.m., ABC, TV-PG).

On “48 Hours Mystery” (10 p.m., CBS): Hippies discover that homicide can harsh their mellow.

Sunday’s highlights

Scheduled on “60 Minutes” (7 p.m., CBS): disgraced NFL quarterback Michael Vick.

A unicorn’s murder shocks Camelot on “Merlin” (8 p.m., NBC, TV-PG).

A mysterious power outage brings Antares “down-to-Earth” on “Defying Gravity” (10 p.m., ABC, TV-14).