”The Millers” (Richard Cartwright/CBS)

RETURNING SHOW: Elena goes to college in the Season 5 premiere of “The Vampire Diaries” (CW at 8), and everything seems great. She just had a romantic summer with Damon and has moved into the dorm with Caroline. Unfortunately, the happiness is short-lived when a new student named Megan announces she’ll be their third roommate.

SERIES PREMIERE: It’s October, so Nickelodeon gets spooky with new series “Deadtime Stories” (at 8), which stars Jennifer Stone as a babysitter who shares horror stories every week, starting with one about zombies.

Kristen Bell plays a snobby Eagleton council member on “Parks and Recreation” (NBC at 8) who clashes with Leslie; later, with Andy in London, Ann takes April to enroll in vet school.

SERIES PREMIERE: Will Arnett is back with another shot at a prime-time comedy with “The Millers” (CBS at 8:30), playing a divorced news reporter who is psyched to live the single life — until his dad (Beau Bridges) decides to leave his wife (Margo Martindale) of 43 years, meaning his mom suddenly moves in to his bachelor pad.

Demi Lovato starts her guest-stint on “Glee” (Fox at 9) as a love interest for Santana, who gets a waitress gig with Rachel at a diner to make ends meet in New York.

SERIES PREMIERE: E! investigates various pop culture trends on new series “Society X With Laura Ling” (at 10), beginning with a report on the world of synthetic drugs.

RETURNING SHOW: Uh-oh. The president’s wife outed “professional fixer” Olivia Pope as her husband’s mistress on the finale of “Scandal” (ABC at 10), which means Pope & Associates scrambles to deal with the biggest scandal ever on the Season 3 opener. Meanwhile, Olivia’s father is back in the picture, and is determined to carry out an evil plot.

Actress Emmy Rossum stops by “Project Runway” (Lifetime at 9) to guest judge a challenge involving avant-garde looks, while the contestants get nervous after a double elimination.

News anchor Brian Williams is on “Late Show With David Letterman” (CBS at 11:35), along with Stupid Human Tricks and a performance from the musical film “Muscle Shoals.”

“The Tonight Show With Jay Leno” (NBC at 11:35) hosts actress Julianne Moore, actor Billy Gardell and musical guest Stone Temple Pilots with Chester Bennington.

Singer John Mayer and actress Katie Lowes are on “Jimmy Kimmel Live” (ABC at 11:35).

— Emily Yahr