Kelvin wakes in a magical world with no memory of the life he left behind, having traded those memories to the goddess Melfina for a set of abilities that make him an S-rank summoner from his first day. Melfina becomes his first follower, and Kelvin registers as an adventurer and sets out, binding monsters and spirits to his side as he travels. A battle junkie by his own account, he keeps looking for opponents strong enough to make the fight worth having.