A man longing for a warm family is reincarnated as Prince Asha, the unwanted eldest son of the magical Iscalion Empire. Considered too tainted by his bloodline to be a legitimate heir, Asha is cast aside and separated from his younger siblings from birth. Giving up on attaining the throne, he embraces his newfound freedom and dives headfirst into alchemy as his personal playground. However, his overflowing talent, combined with memories of modern science, leads him to accidentally invent world-shaking technologies. Even as nobles try to oppose him, his creations allow him to unintentionally dominate the imperial succession war. His true motivation, though, is not power but a simple desire to be called big brother someday.

The story follows Asha, a genius alchemist whose inventions disrupt the political hierarchy. He is supported by his father, the current emperor, who is looked down upon by subjects due to his low bloodline. Key narrative arcs involve Asha working to raise his father's status and strengthen the authority of a younger brother who is meant to legitimately succeed the throne. This includes orchestrating events such as the Emperor's Salon, where Asha demonstrates alchemy publicly to leave a lasting impression on the imperial aristocracy. He also plans a heartfelt scheme to play with his younger brothers and sisters, aiming to create lasting memories. The series balances political maneuvering with heartwarming family themes as Asha navigates a complicated situation where he has little influence and nearly everyone is against him.