Inspector Appleby's aunt is most distressed when her horse, Daffodil—a somewhat half-witted animal with exceptional numerical skills—goes missing from her stable in Harrogate. Meanwhile, Hudspith is hot on the trail of Lucy Rideout, an enigmatic young girl has been whisked away to an unknown isle by a mysterious gentleman. And when a house in Bloomsbury, supposedly haunted, also goes missing, the baffled policemen search for a connection. As Appleby and Hudspith trace Daffodil and Lucy, the fragments begin to come together and an extravagant project is uncovered, leading them into the South American jungle.