A recently deceased young man is sent to another world and is taught magic by master Merlin. He quickly masters everything he is taught. However he has one fatal weakness, common sense.

A young man who had surely died in an accident, was reborn in another world as a baby. After that, he was picked up by the patriot hero "Sage" Merlin Wolford and was given the name Shin. He was raised as a grandson by Merlin and soaked up Merlin's teachings, earning him some shocking powers; however, when he became 15, his grandfather Merlin said, "I forgot to teach him common sense!" An "abnormal" boy's unconventional other world fantasy life starts here.