For years, Professor Peter Shandy has been badgered in vain by Jemima Ames, Assistant Librarian and Annual Chairperson, to decorate his campus home for the Christmastime Grand Illumination, which is Balaclava Agricultural College's main fund raising event. Now he can hold out no longer. Goaded to madness, he buries his small brick house under an avalanche of plastic reindeer, flashing lights, and fake Santa Clauses, hooks up an amplifier blaring "All I Want for Christmas Is My Two Front Teeth," locks the switches at "on" and escapes to sea on a tramp steamer.

Shipwrecked and conscience-stricken, he crawls back to face his colleagues, and finds Jemima Ames dead on his living room floor. Police and security guards decide it's an accident, but Shandy suspects a crafty murder under the mistletoe. The good professor also suspects that he had better discover the truth without further wrecking the Illumination or the next corpse will be his....