After what appears to be just another ordinary day, middle school student Yoshio Kobayashi wakes up in his classroom to make a terrifying discovery: his teacher has been mutilated, and Yoshio happens to be holding the weapon used to commit the crime. Despite the initial shock of finding himself in this predicament, the curious and detached Yoshio can't help but be secretly thrilled about this attempt to frame him. His put-upon friend Souji Hashiba is turned into a willing accomplice, and together, they are determined to prove Yoshio's innocence. Additionally, Kogorou Akechi, a genius high school detective, has come to the scene of the crime in order to investigate the case and when Kogorou meets the young man found guilty, an intense mutual interest sparks between the two of them. Kobayashi wishes to enter Akechi's world of crime solving as his assistant, and Akechi is determined to see if the enthusiastic boy is up to the challenge. Ranpo Kitan: Game of Laplace is a surreal mystery and horror anime that contains brutal and bizarre crimes, loosely based on stories written by Ranpo Edogawa, who is famous for his influence on Japanese fiction.

Kouhei Araki, a veteran editor of the dictionary editorial division at Genbu Publishing, plans to retire in order to better care for his ailing wife. However, before retiring, he must find a replacement to complete his latest project: a new dictionary called The Great Passage. But no matter where he looks, he cannot find anyone suitable, as making a dictionary requires a wealth of patience, time, and dedication. Mitsuya Majime works in Genbu Publishing's sales division, yet he has poor social skills and an inability to read the mood in most situations. In spite of this, he excels at having an enthusiasm for words thanks to his love of reading and careful personality. It is these skills that draw Araki to him and prompt him to offer Majime a position in the dictionary editorial department. As Majime accepts his new position, he finds himself unsure of his abilities and questioning whether he will fit in with his new co-workers. Yet amid the vast sea of words, The Great Passage will bring them together.