Famed personal eye Hercule Poirot tackles worldwide intrigue and espionage within this traditional Agatha Christie mystery.

Framed in the doorway of Hercule Poirot’s bedroom stands an uninvited guest, coated from check out foot in dust particles. The person stares for a moment, then he sways and falls. Who is he? Is certainly he suffering from shock or simply exhaustion? Most importantly, what is the importance of the number 4, scribbled again and again on a sheet of paper?

Poirot sees himself plunged into a globe of international intrigue, risking his life-and that of his ‘twin brother’-to uncover the reality.