Prosaically titled The Mysterious Disappearances in the original UK edition the story takes the form of a detective novel opening with the theft of diamonds and gems from a jeweler's office and several apparent murders. The biggest mystery that plagues the several policemen from Scotland yard tackling the various crimes, accidents and vanishings is the fact that the victims' bodies cannot be found. Among the many baffling and inexplicable events the police face:
- A jeweler disappears from his locked office. There is only one door watched by two clerks who saw only a single visitor enter and exit during the work day.
- The body of a Maharajah disappears from a plane crash site with no sign of footprints or any other disturbances surrounding the wreckage.
- A policeman enters a building in full view of his colleagues but never returns. A search of the house reveals it to be completely empty of inhabitants.
The book has a somber often humorless tone thanks in large part to the extremely uptight Henry Fordyce as narrator. But the adventures and multiple puzzles keep the reader engaged. Only the introduction of the at times sappy love story subplot periodically detract from what otherwise is an intriguing mystery that soon becomes a science fiction adventure. In the final chapters Seymour's experimental work is revealed to be an early form of quantum mechanics and particle physics. Fordyce finds himself rendering those experiments in very basic layman's terms in an attempt to convey the often difficult mathematics involved which he confesses he does not understand at all.