Initially published as a serialized manga, the collected paperback book sold over 400,000 copies in Japan and attracted a film adaptation.

[1][2] The story is told from the point of view of an Akita dog named Happie, adopted by a working-class Japanese family as a puppy and lives with them for several years.

This story begins right where Stargazing Dog ends, when Okutsu, a middle age social worker receives the assignment to locate Daddy's family to inform them about his death.

Eventually Okutsu understands Daddy and Happie's life is a parable of the way as goes the people live, and comes to the conclusion that in the end, we all are like a stargazing dog, always dreaming a way to reach the impossible.

Unable to locate any relatives since Daddy intentionally destroyed all traces of his past, Okutsu decides to authorize the cremation of his remains as an unidentified person, and disperses his ashes around Happie's grave, which coincidentally is in the middle of a sunflower field like the one next to his grandfather's home.

In Twin Star, we discover that Happie was chosen by Miku as her pet for being an hyperactive healthy dog, while his brother Chibi was discarded due to his delicate and sickly look.

The dog was born with a heart condition, so is left to die in a cardboard box, but later adopted by Mrs. Nagano, an old, grumpy, and unfriendly woman who also has delicate health.

By coincidence, while looking for Daddy to return his stolen wallet, Tetsuo, his grandfather, and his dog, Happie, meet Mrs. Nagano and Chibi in a local cherry-tree field.

Briefly connected to the original story, these three additional narrations expands Happie's universe, implying that every thing we do, even a little moment in time, can have large repercussions on others and change their lives, even if we never have contact with them.

The Spanish edition of Stargazing Dog, "El Perro Enamorado de las Estrellas" published by Ponent Mon editorial in Spain compiles all five stories in one single volume with the same title.

In Latin America, all five stories were published by Kamite as "El Perro Guardián de las Estrellas" respecting the original 2 volume format of Futabasha.