Show of the week: Appropriate Adult

This gripping, fact-based drama chronicles the strange relationship between British serial killer Fred West, who was responsible for the murders of more than a dozen young women, and Janet Leach, a social worker appointed to protect West’s interests during questioning. As the killer, Dominic West (The Wire) embodies the banality of evil—he’s a sociopath utterly matter-of-fact about acts of monstrous cruelty. Emily Watson (Breaking the Waves) is no less remarkable in credibly portraying an ordinary woman who grows too close to a monster. Saturday, Dec. 10, at 10 p.m., Sundance Channel