Marusya Levkova has barely recovered from the recent tragedies that struck the small town of Chkalovsk, when something terrible happens again - an elderly man is killed and robbed in a dark gateway. Marusya, by chance, meets a friend of the deceased and again starts a dangerous investigation because she cannot stay away. As she begins to unravel the mysteries, she does not yet suspect that she will have to plunge into the past - during the difficult years of the war - and face a brutal killer. "Access Code" is a fascinating detective novel that immerses the reader in a dangerous world with secret laboratories, German spies and secret research buried deep underground. Marusya Levkova bravely leads the investigation and follows in the footsteps of the killer. Writer Marta Jaskol has written an exciting detective story in which readers, together with the main character Marusya, can unravel a complex case and plunge into the past.