It is the second of four mysteries featuring The Great Merlini, a stage magician and Rawson's favorite protagonist.

Ross Harte, publicity writer, is investigating the person behind a classified ad seeking a haunted house for sale.

When it turns out to be his old friend The Great Merlini, Harte drops by his store, The Magic Shop, looking for an explanation.

The plot soon expands to involve a psychic researcher and his favourite medium, a group of treasure hunters seeking a sunken treasure, counterfeit golden guinea coins, a man with blue skin (argyria), a gangster named Charles Lamb, a second murder by "the bends", and a murder scene with a set of neat footprints marching across the ceiling.

Merlini survives more than one attempt on his life before he can call in the police and conclusively bring the crimes home to the guilty.