Growing up amidst the harsh conditions of the Yokohama slums, Akutagawa Ryuunosuke remained oblivious to his lung disease until a Mafia-enforced medical examination at the age of 13. By the time he discovered it, the damage was irreparable. He toiled tirelessly, pushing himself to the brink of exhaustion, the persistent coughing of blood a haunting reminder of his deteriorating health, exacerbated by a smoking habit he had developed.

His demeanor mirrored his harsh circumstances—stubborn and cold to most, sparing warmth for only a select few. Among those, while begrudgingly, was Nakajima Atsushi, the weretiger of the rivaling Armed Detective Agency. Initially, their conflicting allegiances were an advantage, but as the Port Mafia and the Agency formed an uneasy alliance, Akutagawa found himself unable to confront Atsushi directly, who now served as his partner on numerous cases.

Atsushi's inherent kindness, in stark contrast to Akutagawa's cold exterior, eventually thawed the icy relationship. Surprisingly, they transitioned from adversaries to confidants, and after a series of heartfelt conversations, they embarked on an unexpected journey of dating. Akutagawa, grappling with the absurdity of it all, —He started another habit picked up from his superior, Nakahara Chuuya. Unbeknownst to Chuuya, Akutagawa harbored a lung disease, a secret shared only with Atsushi, whom he hadn't revealed his smoking habit to.

With the dim glow of the moon above, Akutagawa leaned against the balcony railing, cigarette in hand, it was something he did once he knew Atsushi was asleep. The cool breeze played with his short black hair as he exhaled a puff of smoke, watching it dissipate into the dark night. The serenity shattered as the balcony door clicked open, prompting Akutagawa to assume a defensive stance, only to relax upon realizing it was a drowsy Atsushi.

"Atsushi." His voice, hushed, broke the stillness. The cigarette dangled from his fingers, a silent admission of a habit he had kept hidden until now.