Christmas is approaching, but it is not the same as the nuclear holocaust has ruined much of the world's evergreen tree population. While cleaning out the chimney, the group finds Santa Claus has visited the group, but appears depressed. He later reveals to the group that he is suffering survivor's guilt as his workshop at the North Pole had a fallout shelter, but the door slammed shut and Mrs. Claus and all the elves were unable to get inside. Stuart Pankin guest starred as Santa.

• June Whitfield
• John Levene
• Patrick Troughton