Lennox Davies couldn't be happier when the detective agency of Whitney and Davies receives a summons to investigate a missing secretary at the magical college of Saint Dorothea's in Cambridge. He envisions a charming locked room puzzle, to be followed by strolling the streets of the ancient and beautiful university city with his friend and partner in detection Maia Whitney. What could be better?

But delight soon turns to dismay when a man is murdered. Not only that, the missing secretary seems to have vanished into the morning mists off the River Cam. Will Maia and Len be able to catch the killer before the secretary's dead body turns up as well? Or is it already too late? Before long even the bond between partners is strained as Len and Maia find themselves at odds over their values.

What began as a clever exercise in deduction turns into their most challenging mystery yet, and one that could result in the end of Whitney and Davies ... forever.