Sirius is a descendant of the first people-like stellas - Yorikiri. He leads a carefree life with his dad Yorikiri, companion Soročić, best friend Rigel and others in the walls of the Stella Citadel. One day he sees the fall of another star, Orion, and falls down from Stellarium to save him, so here his adventure begins!

From Orion he learns about Outher Space and other stars in the vast space. He also learns a lot about life in Locus (the space under Stellarium) where ordinary people live and makes many friends. Sirius reveals things about his origins, suffers the loss of his father, and goes into Outer Space with Orion and Rigel to save Locus. Despite many losses during his adventure, he matures but doesn't lose his kindness and bright spirit.

Sirius matures greatly after returning from outer space, both externally and internally. His tenderness and kindness still remain, but with them comes determination and inner wisdom. His words are always filled with sincere gentleness and encourage to those who hear it. His hair fades and turns white at the ends; eyes seem to look more "mature" and "deep". Orion taught Sirius to use healing with his Star Core. This is a difficult and energy-consuming process.

In the end, Sirius with his friends (Rigel and Orion) becomes the constellation we know (Canis Major), and his Star Core shines brightest.