Edinburgh, 1888. A violinist is murdered in his home. The dead virtuoso’s maid swears she heard three musicians playing in the night. But with only one body in the locked practice room – and no way in or out – the case makes no sense.

Fearing a national panic over another Ripper, Scotland Yard sends Inspector Ian Frey to investigate under the cover of a fake department specializing in the occult. However, Frey’s new boss, Detective ‘Nine-Nails’ McGray, actually believes in such supernatural nonsense.

McGray’s tragic past has driven him to superstition, but even Frey must admit that this case seems beyond reason.