Romanos D' Diogenes and the Secret of the First - Mystery in Istanbul

A school trip to Istanbul. Sophia and Manolis, twins from Alimos, travel with their class to their grandmother's hometown, about whom they have heard so much... In the First, on the smallest island of the Princes' Islands, in the former exile site of Byzantine emperors, where they are going to stay, a precious secret has been well hidden for centuries.

Through lively stories and on-site visits to Pera, the Phanar, the Bosporus, and the Princes' Islands, the old and recent history of the Greek community in Istanbul comes alive before them, as the two siblings and their friends try to solve a riddle composed of three lines of four mysterious letters and a forgotten oath of silence.

The appearance of two dark figures, who have become shadows to them, adds tension and suspense to their efforts…