Seasons of Books and Keys is a visual novel video game developed by iMel and published by Shueisha Games.

About

The two members of the library committee keep finding requests dropped in their laps. A cheerful upperclassman brings them a safe that will not open. Exam questions vanish. A student who took their own life leaves behind the last book they read.

And then there is the secret that the partner is carrying. What begins as a small favor in an ordinary school day slowly swings open the door onto someone’s secret, or someone’s lie.

The game adapts Seasons of Books and Keys, the author behind Hyouka, the Shoushimin series, and The Samurai and the Prisoner, and originally published by SHUEISHA.Inc.

Its full scenario is presented with rich color illustration and complete voice acting, and it adds an all-new episode, Vintage Strange Stories, written for this release by Yonezawa himself.

The main character leads are drawn by Yoko Tanji, the illustrator who created the original novel’s key visual.

Players step into the role of Jiro Horikawa, one half of the duo, listening to each request that comes into the library and threading the small inconsistencies together until the door to the truth opens.

The truth behind each client, the secret his partner keeps, and where the friendship between the two boys finally leads: it all waits inside.

Characters

• Jiro Horikawa (voiced by Kazuki Ura) – People are forever bringing him their problems, and he tends to believe them. Beneath that easygoing manner is a sharp eye for detail. Ever since he started spending time with Matsukura, he keeps finding himself tangled up in strange situations.
• Shimon Matsukura (voiced by Yuichirou Umehara) – Sardonic, and older than his years in the way he thinks. Tall and good-looking, he stands out in any room. Ever since he started spending time with Horikawa, he keeps finding himself tangled up in strange situations.

About the Original Novel: The Season of Book and Key

The author, Honobu Yonezawa, made his debut in 2001 when Hyouka, earned an Encouragement Award in the young mystery and horror category of the 5th Kadokawa Gakuen Novel Prize. The Kotenbu series that began with Hyouka, became a bestseller and was adapted into anime, manga, and a live-action film. Yonezawa won the 64th Mystery Writers of Japan Award for Oreta Ryukotsu in 2011, and the 27th Yamamoto Shugoro Award for Mangan in 2014.

In 2021, The Samurai and the Prisoner won the 12th Yamada Futaro Award, and the following year the same novel took both the 166th Naoki Prize and the 22nd Honkaku Mystery Award. The Samurai and the Prisoner topped all four of Japan’s major annual mystery rankings, the first title ever to sweep every one of them. In 2025, the Shoushimin series won the 10th Yoshikawa Eiji Bunko Prize.

Seasons of Books and Keys is the first volume of the Toshoiin series, with a cumulative print run of more than 400,000 copies.

The second volume, Seasons of Bookmarks and Lies, is also on sale.