Ellie McDonnell is about to embark on her most perilous mission yet: go to Lisbon, Portugal to save her beloved cousin Toby who has reportedly escaped from a German prisoner of war camp. Toby has been missing since the Battle of Dunkirk and Ellie had all but lost hope in ever seeing him again until Major Ramsey, the British military intelligence officer she had been working closely with over the past few months, shared the news he’d intercepted.

Nothing will stop Ellie from finding her cousin, not even the awkward experience of having to travel to an unknown country with Ramsey after he’d dismissed her for being untrustworthy just as she’d realised she had fallen in love with him. Under the supervision of Captain Archie Blandings, a charming intelligence officer based in Lisbon, Ellie meets with undercover operatives to track down where Toby might be hiding from the Nazis and whether they are too late to safely recover him, all the while fighting her feelings for Ramsey and the incessant burden of war looming around her at every turn.