Volume 1: Dear Mr. Rain Kutsuna Satoru, a hat maker, picks up a man collapsed on the side of the road named Kashiba Ryou, who came to Japan to die. Volumes 2-3: Dear Hatter Volumes 4-7: The Speaker

Canis: Dear Mr. Rain was published digitally in English by FAKKU under the KUMA imprint on June 23, 2020, and in print on September 22, 2020. Subsequent volumes have been published by Denpa under the same imprint. Another edition of Canis: Dear Mr. Rain was published by Denpa on November 15, 2022. It has also been published in Polish by Dango since 2021, and in Spanish by Milky Way Ediciones since January 31, 2019.