DAVID WIEGAND

The Discovery Channel continues “Shark Week” with “Shark Vortex ” at 8 p.m., “Return to the Isle of Jaws ”at 9p.m. “Alien Sharks: Stranger Fins ”at 10 p.m., and “Shark After Dark” at 11 p.m. with Vicky Vasquez and Anthony Jeselnik. Nat Geo Wild ’s“Shark Week” continues with “Tiger Shark Terror ”at8 p.m. NBC premieres “Midnight, Texas,” at 10 p.m., based on the novels of Charlaine Harris, about a town full of spooks, aliens and weirdos, starring Francois Arnaud as a real psychic who pretends to be a phony. If there’s any justice, the show will be canceled at 12:01. Paula Patton stars in the new ABC limited drama “Somewhere Between,” premiering at a special night and time at 10:01 p.m. She plays a mother who travels back in time to prevent her daughter’s murder. The show is based on the book “God’s Gift: 14 Days,” and co-stars Devon Sawa. “People of Earth” sends season two into orbit on TBS at 10:30 p.m. The show stars Wyatt Cenac and Ana Gasteyer and is very funny. It’s about a support group for people who have been abducted by aliens.

Conan O’Brien co-created it.

Among Acorn TV’s offerings for the day is the U.S. premiere of “Murdoch Mysteries: Once Upon a Murdoch Christmas,” the feature-length special from season 10, starring Yannick Bisson as Detective William Murdoch.

Historian David Starkey hosts “The Churchills,” an Acorn exclusive about two of Britain’s greatest war leaders, John Churchill, Duke of Marlborough, who squared off against Louis XIV of France, and his descendant, Sir Winston, who was instrumental in the Allies’ defeat of Nazi Germany in World War II. This is a three-part documentary, and if you’ve caught other films narrated by Starkey, you know he brings a wealth of knowledge to his subject matter.

Also from Acorn: The season-three finale of “Janet King” (episodes 7 and 8) and the season finale of “Loch Ness.” Go to www.acorn.tv.