Each December, the faculty of Balaclava Agricultural College goes wild with holiday decorations. The entire campus glitters with Christmas lights, save for one dark spot: the home of professor Peter Shandy. But after years of resisting the school's Illumination festival, Shandy suddenly snaps, installing a million-watt display of flashing lights and blaring music perfectly calculated to drive his neighbors mad. Then the horticulturalist flees town, planning to spend Christmas on a tramp steamer. It's not long before he feels guilty about his prank and returns home to find his lights extinguished--and a dead librarian in his living room.

Hoping to avoid a scandal, the school's head asks Shandy, sometimes detective, to investigate the matter quietly. After all, Christmas is big business, and the town needs the cash infusion that typically comes with the Illumination. But as Shandy will soon find out, there's a dark side to even the whitest of white Christmases.