When Miles Hammond is invited to a meeting of the Murder Club in London, he is met instead with just two other guests and is treated to a strange tale of an impossible crime in France years before; the murder of a man on a tower with only one staircase, under watch at the time at which the murder took place. With theories of levitating vampires abounding, the story comes home to Miles when he realises that the librarian he has just hired for his home is none other than Fay Seton, a woman at the heart of this bizarre and unsolved past murder. Carr considered this novel one of his best works, and it is easy to see why when experiencing its ingenious plot delivered with an astounding pace and masterfully drawn characters including none other than the great detective Dr Gideon Fell.