He was born in Szabadka, then in Hungary, but it became Subotica and part of Yugoslavia following the 1920 Treaty of Trianon.

While on holiday in the south of France, he sends a roll of camera film for development, however, it turns out to contain pictures which are not his, of nearby naval defences.

The police realise that Vadassy did not take the pictures, but that someone else at his hotel must have an identical camera, a Zeiss Ikon Contax.

Vadassy is told to return to the hotel to find the real spy, with the threat that should he fail to do so, he will be deported, which could mean death.

[2] The book contained early descriptions of German concentration camps, based on Ambler's conversations with refugees and reading of left-wing newspapers.