The drama tells the story of a full-time housewife, Miu Kanzaki (Wakana Matsumoto), who suffers from emotional violence from her husband Hiroki Kanzaki (Kei Tanaka) and lives like a bird in a cage. She unexpectedly reunites with her childhood sweetheart Ryo Fuyutsuki (Tatsuya Fukasawa) and becomes pregnant after spending a night together. In order to protect the treasure left by her loved one, she decides to become a villain and lies that her and Fuyutsuki's child is Hiroki's child, and lets him raise it. However, this forbidden decision to "lay an egg" violently disrupts the intertwined fate of Miu, Hiroki, and Fuyutsuki.