In Glasgow, a Soviet sailor is struck by a truck while fleeing from a port guard. Among the dead man's possessions, Preston finds a disk of polonium, which could only be useful as a component of a detonator for a bomb. He informs Harcourt-Smith, but is promptly suspended, as Harcourt-Smith believes that Preston is manufacturing a fake incident to work his way back into MI5. Preston, however has the confidence of Sir Bernard Hemmings, the gravely-ill Director of MI5, as well as Irvine, who is happy to sidestep Harcourt-Smith's directives. Preston sets to work and eventually comes across Winkler, a known Czech KGB agent, and tails him from the airport.