Christmas is a time for watching movies. Every year, television schedules are packed with holiday classics, and the internet is awash with lists of the greatest festive features—from It’s a Wonderful Life to The Muppet Christmas Carol. Occasionally, some unconventional choices slip through, like Terry Gilliam’s dystopian comedy Brazil (which features a memorable cameo from Santa Claus) and Stanley Kubrick’s erotic thriller Eyes Wide Shut (which includes Christmas trees and fairy lights in almost every scene). But one classic film is never mentioned in the Christmas movie conversation: Psycho.

Alfred Hitchcock’s 1960 masterpiece is one of the most closely studied movies in film history. More than a dozen books have been written about it—from actress Janet Leigh’s memoir of her time working on the film, to Stephen Rebello’s definitive account of its making (which was itself turned into a movie). There is even a feature-length documentary dedicated solely to the famous shower scene. A handful of these studies have referenced the fact that Psycho is technically a Christmas movie, taking place during the advent season. But none have examined what significance this has for the film’s meaning.

We know Psycho is set during the holidays from the opening scene. Over an establishing shot of a city skyline, Hitchcock superimposes three title cards, giving us a precise location, date, and time:

PHOENIX, ARIZONA
FRIDAY, DECEMBER THE ELEVENTH
TWO FORTY-THREE P.M.

From there, the camera slips through a hotel window to spy on a sinful lunchtime tryst between Marion Crane and her lover Sam. We learn that this is how they always meet. Sam lives 500 miles away in California, so the only moments they have are these stolen lunch hours when Sam can make the journey to Arizona for business. They could get married. But the divorced Sam makes excuses about his alimony debts to deflect the suggestion.

On returning to the office from her lunch break, Marion makes an impulsive decision: she steals $40,000 from a client, hoping it can buy her a new, more respectable life with Sam. On the way to California, she sleeps one night by the side of the road in her car. On the second, she finds shelter in the Bates Motel, a secluded establishment run by the charming but emotionally stunted Norman Bates. By now, it is Saturday 12 December. And this is the night Marion meets a grisly end—stabbed to death in her motel shower.

From there, the narrative skips forward one week to Saturday 19 December. Hitchcock signposts this clearly with a close-up of Sam writing a letter to the missing Marion dated “Saturday.” When Marion’s sister and a private investigator arrive, they confirm the date by explaining that Marion disappeared a week ago. The private investigator heads out to the Bates Motel, to become the film’s second murder victim. The action draws to a close the following day, when Sam and Marion’s sister finally apprehend Norman as the culprit.

As this synopsis shows, the film’s timeline can be precisely traced from 11 December to 20 December—right in the heart of the advent season. But Psycho is rarely acknowledged as a Christmas film because these dates are never specifically stated after that opening title card. Nor do any characters ever reference the holiday season. The closest we get is an offhand comment from Marion, which could be an allusion to the upcoming new year. “Headaches are like resolutions,” she says. “You forget them as soon as they stop hurting.”