Dr Watson has been invited to Crain Manor, where his old friend James Crain is to hold a spiritualist gathering. During a séance a ghostly figure is seen, supposedly the spirit of Sybille, the first Lady Crain, who murdered her husband in the tower room, and whose appearance is said to be a sign of disaster.

In an attempt to debunk the seance, James's sister Esther declares that she will sleep in the tower room - but at midnight there is a bloodcurdling scream and Esther is found dead, a look of horror on her face, and the room locked from the inside.

Watson sends for Sherlock Holmes to investigate the tragic death. But it will be anything but straightforward, as there are those who do not want him to succeed...