Ranpo's deduction scenes stop the show cold because they're not about flashy reveals, they're about watching someone see what everyone else missed, then explain it like he's the only smart person in the room. Season 4 finally knows what it actually is: a character study wrapped in mystery, where the jokes land because you've earned the right to laugh at these people. The backflash sequences hit different here, showing you why each member of the Agency needed to exist before the Agency even could.

Fukuzawa has left the military behind, setting up shop as an independent bodyguard relying on his razor-sharp sword skills. His new venture isn't exactly thriving until he meets Ranpo Edogawa, a sharp-tongued kid. What starts as a chance encounter over a gruesome murder becomes the spark for something bigger: the Armed Detective Agency. Now the Agency faces a case that spirals into something far more sinister. A criminal with the ability to engineer perfect crimes has emerged, and as Ranpo pursues them, he uncovers a scheme meant to wipe out the Agency completely. Though warned about the trap, the detectives press forward anyway, and they end up blamed for the very crimes they were chasing. Labeled as terrorists, the members who remain must clear their names, even if that means seeking help from their bitter enemies.