The year is 1907. A fight breaks out in one of the Kyiv theaters. A respectable Austrian gentleman publicly accuses a boy messenger of theft. Without a shadow of fear, the teenager rejects the accusation, not yet suspecting that this is the first exam, a pass to a new life. After all, under a green cap, an elderly Austrian Herr Friedrich saw not only a disguised girl, but also a potential pupil for his orphanage - the secret school Artemis", where professional spies are trained.