Hachinan tte, Sore wa Nai Deshou!八男って、それはないでしょう!; The 8th Son? Are You Kidding Me?; 八男？别闹了！; 팔남이라니, 그건 아니잖아요!; O 8º Filho? Você Está Brincando Comigo?; ¿El octavo hijo? ¡Eso no puede ser cierto!; Восьмой сын? Да не может этого быть!; хатинан ттэ, сорэ ва най дэсё:; ผมเนี่ยนะ...ชายแปด!

Ichinomiya Shingo, a young 25 years old, single, company worker, while thinking of tomorrow’s busy working day goes to sleep. However the moment he woke up, it was a room unknown to him. He then learned that he was inside a 6 years-old boy and had taken over his mind. Furthermore he learned a lot from the memories of said boy: he was born as the youngest child (8th son and 10th child) of a poor noble family living in the back country. Having no administrative skill, he couldn’t do anything to manage the vast land his family has. Fortunately, he was blessed with a very rare talent, talent of magic. Unfortunately, while his talent could bring prosperity to his family, in his situation it only brought disaster. Yes, this is the story of the boy, Wendelin von Benno Baumeister, opening his own path in a harsh world.