Rain, a battle-hardened bodyguard raised in the chaos of war, is assigned to protect Victoria, the heiress of a financial conglomerate. He is a master of firearms, explosives, and tactical infiltration—yet he has no idea what a ""normal life"" means. In his logic, a suspicious love letter in a locker equals a bomb, football practice equals hand-to-hand combat, and attending an upper-class gala equals a high-risk counter-terrorism mission. After he blows the school apart beyond recognition, Victoria's campus life is never peaceful again. She becomes the only one who tries to stop Rain from militarizing everything, while Rain carries out his ""protection mission"" with an ever-stern face. She is a chaebol heiress longing for an ordinary life; he is a soldier from the battlefield who doesn't even know what ""ordinary"" means. Every mundane moment between them becomes a collision of chaos and comedy. And what she doesn't know is that Rain's line—""The mission has no end date""—may well be the most awkward love confession in the world.