The darkest day of horror the world has ever known.
In an underground military bunker, scientists and soldiers bicker about the best way to handle the zombie menace that has overtaken the world. Only the lazy black guy and the drunken Mr. Bean have the right idea to leave the zombie-ridden tunnels, but they're both either too lazy or too drunk to embark on such a retreat.
The film begins in October, with a calendar beginning on Tuesday, which is consistent for either 1968, 1974 or 1985.
Nov 4, 1985
The film ends with Sarah marking her hand-drawn calendar with an 'X' on November 4th (inaccurately beginning the month in Monday's position, which November 1st wouldn't fall on a Monday until 1993). Since this happens soon after the escape from the underground bunker (they're still wearing the same clothes), this calendar is simply inaccurate. Sarah, the black guy, and Mr. Bean all probably forgot what day of the week it was, and decided to start over, just as the black guy had suggested earlier.