To Emily the prospect of a cultural holiday in Leningrad seemed rather dull, until an adventure presented itself the moment she and her family stepped off the plane at Leningrad airport.
For who was the mysterious Mrs Hannay accompanying them on their tour? And why was her photograph kept by the authorities at Leningrad Airport?
Was their Russian guide, the amiable Mr Oblamov, really trailing Mrs Hannay, waiting for a false move?
And what was the connection between Mrs Hannay, the Dubinsky family and the Leonardo da Vinci in the Hermitage Museum?
Emily felt sure she knew the answer to the mystery and, together with her sister Alyce, was determined to act.