ある日　犬の国から手紙が来て

Shota, a young boy, cherishes his dog Koro, who is diagnosed with a terminal illness and given only three months to live. Regretting his recent neglect, Shota takes Koro, now frail, in a cart to the mountain they used to climb together, creating one last memory. After Koro’s passing, Shota receives a letter from the “Dog Nation,” a place where departed dogs live happily. The letter, written by Koro, reflects on their bond and brings Shota comfort. Through interactions with other characters and their dogs, like a girl with a sickly puppy or a boy with a loyal stray, the manga explores themes of love and loss across various short tales. (Unreviewed summary by Grok 3)