"Molly Unleashed" -- Molly receives some advice from her union while in front of a school board. (Robert Voets/CBS)

Robin and Loretta’s feud escalates, and Barney’s caught in the middle on “How I Met Your Mother” (CBS at 8 p.m.). Marshall and Daphne discover a stowaway on their trip and Ted takes Cassie on a date to a lighthouse.

RETURNING SHOWS: “Real Housewives of Beverly Hills” and “Vanderpump Rules” (Bravo at 8) both return in a combined two-hour premiere when Kyle hosts a cocktail party and hires Lisa’s restaurant to cater the event. New cast members Carlton Gebbia and former Miss Puerto Rico Joyce Giraud are introduced.

When Brennan and Booth are in Buenos Aires for their honeymoon on “Bones” (Fox at 8), it quickly turns into a busman’s holiday when they help a detective, who’s a fan of Brennan’s books, investigate the murder of a Nazi war criminal whose remains were found in a mass grave.

Max and Caroline try to convince a stripper to pretend to be Han’s girlfriend when his mother visits from Korea on “2 Broke Girls” (CBS at 8:30).

When Ichabod disappears, his wife appears to Abbie in a vision with a warning about the Headless Horseman’s return on “Sleepy Hollow” (Fox at 9). Abbie consults a recluse to help rid Crane of his nemesis once and for all.

Descend into the shadowy world of black-market organ trafficking with “Tales From the Organ Trade” (HBO at 9), where brokers, rogue surgeons and impoverished men and women are willing to sacrifice an organ for a quick payday and desperate patients face the agonizing choice of obeying the law or saving their lives.

RETURNING SHOW: In the Season 4 opener of “Mike & Molly” (CBS at 9), Molly makes a monumental decision regarding her teaching career.

Alex seeks investigative assistance from her dad once she believes that a death-row inmate was wrongly convicted on “Castle” (ABC at 10). They have only 72 hours to reexamine the original case before the inmate’s scheduled execution.

Boston Red Sox designated hitter David Ortiz and actor Woody Harrelson come to “The Late Show With David Letterman” (CBS at 11:35), with musical guests the Wanted.

Actor Anthony Hopkins guests on “The Tonight Show With Jay Leno” (NBC at 11:35), along with musical artist Sting.

Actors Chris Hemsworth and Artie Lang are on “Jimmy Kimmel Live” (ABC at 11:35), with a musical performance by Jane’s Addiction.

— Rachel Lubitz