In the latest season of Bungou Stray Dogs, Yukichi Fukuzawa shifts his focus from military matters to becoming a solo mercenary with exceptional sword skills. However, his venture into freelance bodyguarding hits a hurdle until he encounters Ranpo Edogawa, a cheeky young boy. Their initial meeting involves a peculiar murder case that leads to the establishment of the Armed Detective Agency. Ranpo takes on the task of apprehending a highly skilled individual capable of committing flawless crimes. As he delves deeper into the investigation, he uncovers a sinister scheme aimed at destroying the Agency completely. Despite being warned about the impending danger, the Agency persists in pursuing the culprits, only to find themselves framed for a crime they didn't commit. Branded as wanted fugitives, the remaining members must clear their names, even if it means seeking help from their sworn adversaries.