RETURNING SHOW: The girls on “Pretty Little Liars” (ABC at 8 p.m.) seem to go back and forth on trusting Mona — one day she’s a psychopath, the next she’s a friend — but on the Season 4 premiere, they team up with her to learn more about their mysterious and terrifying stalker, “A.” Meanwhile, Aria dreads seeing her former high school teacher-turned-boyfriend after their breakup.

As the judges narrow the field during auditions for the Top 20 on “So You Think You Can Dance” (Fox at 8), some lucky dancers head to Las Vegas for callbacks.

SERIES PREMIERE: A charismatic but troubled 16-year-old returns home after spending time in a juvenile detention facility on ABC Family’s dark new drama “Twisted” (at 9), and reconnects with his best friends. Unfortunately, his homecoming celebration is short-lived, as he quickly becomes a suspect in the death of a female classmate.

On “Family S.O.S. With Jo Frost” (TLC at 9), Jo must intervene when a mom is on the verge of leaving her husband, whose impatience is causing a rift within the family, which already has a son in legal trouble.

The captains must deal with a particularly brutal storm that causes lots of problems on “Deadliest Catch” (Discovery at 9).

SERIES PREMIERE: Viewers seemed to enjoy a 2012 special titled “My Teen Is Pregnant & So Am I” (TLC at 10), so the network has turned it into a full docu-series. As the title suggests, the show follows moms and teen daughters who are due to have a baby around the same time.

Several teams compete to get out of a maze on the competition series “Exit” (Syfy at 10), as a pair of exes go up against a husband-and-wife team along with some models and lifeguards.

“Matilda the Musical” didn’t walk away with the big prize at the Tony Awards, but the cast members still stop by “The Late Show With David Letterman” (CBS at 11:35) for a performance; other guests include comedian Dana Carvey and actor Nick Robinson.

Actor Jamie Foxx, tennis star Jimmy Connors and singer Matthew Morrison are on “The Tonight Show With Jay Leno” (NBC at 11:35).

“Jimmy Kimmel Live” (ABC at 11:35) hosts rapper Lil Wayne, actor Chris Messina and musical guest Jimmy Eat World.

— Emily Yahr