It's Miss Tilley's ninetieth birthday and the town of Tinker's Cove is throwing a big birthday party for the former librarian. But when local attorney Sherman Cobb is found murdered and Miss Tilley's long-lost niece suddenly appears in town, Lucy Stone suspects that something sinister is going on. If Lucy doesn't find the killer fast, she and Miss Tilley won't live long enough to make a wish and blow out the candles on this year's birthday cake.