Grandpa is Summoned

While protecting his grandson from a burglar, Seitaro Asao, a tea plantation owner, gets stabbed to death. A slight mix-up by a goddess gets him, instead of his grandson, accidentally summoned to another world. Seitaro accepts to take his grandson's place and starts his new life in the new world as a man ten years younger. Things are quite eventful from the start, but the gods work in mysterious ways, and wisdom and protection from the goddess helps him overcome all obstacles.