An investigator from the future is sent back in time to retrieve an almanac of history up to the year 2976 that has mistakenly been sent back to the year 1976. After a couple of false starts being sent back to parallel times and places he finds the almanac, but discovers that 100 copies have been distributed.
A fun episode dealing with the difficult subject of time travel. A gorgeous bit of dialogue at the end when the traveller debates with one of the possessors of an almanac.