One day, seven-year-old Otoka rescues two chicks in the forest — the offspring of a cockatrice, a type of monster resembling a chicken — and is entrusted with their care by their parent. At that very moment, Otoka regains memories of his past life as a 43 year-old Japanese salaryman. Three years later, the chicks Shiro and Kuro have grown into magnificent cockatrices who lays precious eggs every single day, making them targets for Otoka’s siblings. Otoka decides to make a daring escape under the cover of darkness, taking the cockatrices with him. Having finally broken free from his narrow little world, the ten-year-old yearns to travel the globe in complete freedom. Together with his adorable and incredibly powerful chicken-like companions, the boy revels in a carefree journey through this other world, befriending other monsters and taking up the life of an adventurer as he embraces every moment of his new existence.