Gorou Amamiya, a rural obstetrician and devoted fan, finds himself delivering the twins of his favorite idol, Ai Hoshino—before being tragically murdered that very night. Miraculously, he is reborn as Aquamarine, one of Ai’s newborn sons, retaining all his memories. His twin sister, Ruby, likewise harbors memories of her past life as a young patient of his. As they grow under the care of Ai’s talent agency, they must navigate the ruthless and deceptive world of showbiz, balancing ambition, identity, and vengeance. While Ruby pursues the idol dream, Aqua enters the entertainment industry with a hidden mission: to uncover the truth behind Ai’s death.