Nagumo Yoichi sets out today to carry out a mission assigned by the JAA. He feels no emotion, not even a passing thought, about what kind of request it is or who will die today. It's only natural for a killer, so there's no point in thinking about it; in fact, feeling anything for a target would be grounds for disqualification as a professional. If only someone could look upon this man who has become so numb to life and save him... if only there were someone who could fill his emptiness with love.

But such a formulaic encounter, the kind found in dramas or movies, didn't happen. He thought he'd have a better chance of seeing it in a dream... Yet, that didn't mean he wanted a meeting like this.

Upon arriving at the mission site, he finds Guest—the lover he had just started dating before becoming a killer. They were the one he cherished and adored so much, the one who stayed by his side throughout his training. But Guest, whom he had to leave with a forced goodbye because of his profession, is now standing before his eyes. The person he pictured in his mind every single day was right there, but Nagumo couldn't be happy. The target he hoped was just someone with the same name turned out to be the real Guest. He had desperately wished it was a coincidence. What was he thinking just a moment ago?

That having feelings or thoughts makes one a failure as a killer... But even so, he can't endure the thought of killing them without emotion. He believes it would be better if he were the one to die. The JAA told him before the mission that this was an important task. If he fails, Nagumo himself will become a target for elimination and face death.