A massive meteor shower crashes into Tokyo, transforming the city overnight. In the aftermath, people begin manifesting mysterious superpowers called Astros, born from wishes made upon falling stars. This disaster coincides with the death of Kongo Yotsurugi, the aging but beloved boss of the Yotsurugi family, a former yakuza syndicate that has evolved into a powerful business conglomerate rooted in Asakusa. Kongo’s only biological son, the straightforward and warm-hearted Hibaru Yotsurugi, is named his successor. However, at the funeral, Hibaru shocks everyone by voluntarily ceding the leadership to his best friend Terasu, the twelfth adopted son, hoping to avoid internal bloodshed.

The meteor strike plunges the nation into chaos, and the Yotsurugi family fractures. Hibaru’s decision is not accepted peacefully. The first adopted son, the cold and ambitious Shio Yotsurugi, who commands the Hawk Faction, sees himself as the rightful heir. He immediately moves to consolidate power, using violence and his ability to control gravity to dominate. To protect the innocent people of his neighborhood, Hibaru is forced to embrace his own role as a leader. His Astro manifests as explosive firepower in his fists, triggered by a bullet casing left to him by his father. Joined by his loyal friend Terasu, whose Astro creates a nigh-unbreakable shield, Hibaru decides to fight for his family's legacy in a very different way: not through dominance, but by reclaiming his siblings one by one.

The narrative follows Hibaru’s journey through a Tokyo divided by the meteor’s aftermath, where rival factions control different districts. He first heads to Ikebukuro, now under the control of his younger adopted brother Kou Yotsurugi, who wields a four-armed Astro called Asura. After a fierce battle, Kou and the tenth son Kuran are convinced to join Hibaru’s cause rather than remain under the Hawk Faction’s thumb. This begins a pattern of conflict and reconciliation, as Hibaru proves his strength and conviction. Later, the third son, the hot-headed Torazo Yotsurugi, whose Astro, Fist of the North Star, increases his destructive power, seeks an alliance with Hibaru to take down Shio, leading to a full-scale confrontation in Roppongi against Shio’s elite warriors.

As the war escalates, the cast expands to include key allies like Kinpa Yonana, Hibaru’s childhood friend who can turn invisible, and Reri Yotsurugi, a lawyer who can fire time-manipulation missiles. The conflict also reveals deeper mysteries surrounding the meteor shower, including a rare energy source known as Daybreak Ore and the secret history of the Yotsurugi family. The story moves through arcs such as the Plant Zero Arc, which explores the origin of the Astro powers, before culminating in the final Astro Battle Royale Arc. In this tournament-style confrontation, Hibaru must face his most dangerous siblings, including the gravity-defying Shio and the enigmatic eighth son Shikaba. The final battles resolve the succession war, reveal the truth behind the wishes made on the meteor, and determine the future of the Yotsurugi family and the new, superpowered world order.