We’ve been told to expect plenty of “answers” on this final season of “Lost” (8 p.m., ABC). But what if the answers are lame?

Six seasons of baffling mysteries have taught us to exult in the weirdness, so we may be disappointed by the explanations. I’m reminded of how in “A Christmas Story,” Ralphie spent weeks in breathless anticipation, hoping to reveal great secrets with his “Little Orphan Annie” decoder ring, only to discover that it offered nothing but Ovaltine commercials.

In last week’s head-scratcher, the fake Locke leads Sawyer to the earth-shattering discovery that Jacob had scrawled their names all over a cave wall — a revelation astounding enough to recruit Sawyer to Locke’s murky cause.

Excuse me, but Sawyer’s been through a lot. He’s seen Sayid resurrected; he’s seen Juliet live and then die after sitting on top of an H-bomb; he lived in a bear cage eating food from a vending machine; he’s worn women’s glasses; he’s time-traveled all over eternity and relived three years in the 1970s. So why would a little graffiti blow his mind?

The episode’s conclusion stands in confusing contrast with its earlier depiction of Sawyer, hanging out in the ruins of his Dharma shack, pounding down Jack Daniels and listening to punk-rock records. Why would Sawyer, a man with nothing to live for, so eagerly follow Locke, a man who is already dead?

• A timely “Frontline” (8 p.m., PBS, check local listings) travels to Taliban-held territory in northern Afghanistan to profile the forces fighting NATO troops and discover their motivations. This “Frontline” was filmed before the latest offensive in southern Afghanistan and the capture of a key Taliban leader by Pakistani forces.

• Combining the hot pop-culture trend of vampires and the always popular TV genre of forensics, “Explorer: Vampire Forensics” (9 p.m., National Geographic) is sure to be a hit with fans of lugubrious detective work.

• “Behind the Rainbow” on “Independent Lens” (9 p.m., PBS, check local listings) examines what happened to South Africa’s African National Congress after the transition from apartheid to a multiracial government.

Tonight’s other highlights

• Women’s figure skating on the Winter Olympics (7 p.m., NBC).

• The top 12 women perform on “American Idol” (7 p.m., Fox).

• Callen and Sam infiltrate a deadly militia group on “NCIS: Los Angeles” (8 p.m., CBS).

• Alicia receives the unenviable assignment of representing a senior partner in court on “The Good Wife” (9 p.m., CBS).

• A train accident leaves an unclaimed victim on “The Forgotten” (9 p.m., ABC).