Grief‑shrouded by the death of his only surviving family member, picture‑book author Hotaru Yuuyami is trapped in a two‑month writer"s block. Even his childhood friend and editor Tsubaki Uehara pours every ounce of encouragement into him, yet the sorrow remains unshaken. The situation takes a turn when a mysterious mushroom from Hotaru"s garden, Kinoko Inu, suddenly transforms into a dog‑shaped creature. Tsubaki protests loudly, but Hotaru hastily invites the uncanny being into his apartment.
Within a few days of cohabitation, the mushroom‑dog burns Hanako"s last personal items in an attempt to soothe Hotaru"s depression. The partnership between the overworked writer and his mischievous guest proves far more challenging than anticipated, forcing Hotaru to abandon his grief if he truly wishes to tend properly to Kinoko Inu and to nurture the strange bond that may help heal his broken heart in the quiet evenings.
