The Italian series in the Citadel world. Milan, 2030: Diana Cavalieri is a double agent for the secret syndicate Citadel, who infiltrated Manticore, the rival agency that destroyed Citadel eight years ago. Trapped behind enemy lines, Diana has a chance to leave the agency forever, but she has to decide whether to trust a surprising ally: the heir of Manticore Italy, Edo Zani.