Published in the US magazine Ellery Queen Mystery Magazine, 10/1981. Printed in the collection .
Mr. Fortescue informs Mr. Behrens that a Professor Pitt-Hammersley has accused Sir Boris Wykes, the head of the Early Warning System, of being an East German spy named Stefan Sthugutt. It becomes the job of Calder and Behrens' to look at the evidence and see if it looks solid.