When New York crime family heiress Sienna Moretti is ambushed during a negotiation, a mysterious bodyguard with no traceable past, Christian, saves her life. Impressed by his skill, Sienna hires him as her chief of security, unaware he is Zero-7 — a trained assassin sent by their rival Arthur Vance to infiltrate the family and steal a secret bribery ledger.
As they navigate constant dangers side by side, mutual trust and affection grow between them. Christian soon uncovers the devastating truth: Vance murdered his parents, framed the Morettis, and raised him as a weapon for revenge. He chooses to betray his mission and stand firmly by Sienna’s side.
After family patriarch Marcello is killed, Christian teams up with the three Moretti sisters to fight back. They outmaneuver Vance’s all-out offensive, dismantle his criminal network, and finally bring him to justice. Rejecting all power and titles, Christian stays devoted to Sienna. The two leave for Naples, embracing the quiet, peaceful life they have long yearned for.
