After returning to a hero's welcome in Magdalen College, the drama of Stockholm behind him, Giles is tormented by doubts. Was Ahmad Sharif's death in Sorrento really an accident, as the Carabinieri concluded, or was the truth more sinister? Were the two girls with Stephen Salomon at the symposium his latest research fellows, as he claimed, or there for a very different purpose? And what of Fiona's long-held suspicions about their young assistant Aram? Given what she'd just found in her laptop, wasn't it time to start taking them seriously? When MECCAR's director Rashid Yamani unexpectedly invites Giles to Paris to suggest the true source of the DNA switch for Achilles, Giles sets off to Munich in pursuit of the evidence. But Fiona is not convinced. Left to herself, she hatches an ingenious alternative. Though at first reluctant to accept its plausibility, Giles is persuaded by what he finds after hurriedly returning to Sorrento. When Fiona's laboratory work provides another piece of the jigsaw, and Giles translates the content of an old discarded fax in Arabic that she had found in Washington, everything falls into place. But before they can make the next move, Giles must resolve an awesome ethical dilemma.