勇者召喚に巻き込まれたけれど、勇者じゃなかったアラサーおじさん。暗殺者（アサシン）が見ただけでドン引きするような回復魔法の使い手になっていた。

Soutome Tatsuma is a 31-year-old single office worker who enjoys his weekends and holidays off.

Every day, he takes a fifteen-minute bus ride to the nearest station. On the bus, he meets a group of three students who seem like old friends: a handsome boy and two cute twin girls. Despite their friendly appearance, Tatsuma secretly wishes them ill, saying, “I hope your perfect lives blow up.”

But then, he experiences a strange shock that turns out to be a “hero summoning.” However, he didn’t choose to be involved and doesn’t consider himself a hero.

He discovers he has a special power: space magic, like having an item box. Because of this power, he’s directed to the adventurer’s guild for work. They even give him some money, like a hush payment, before sending him to the castle town.

Tatsuma had hoped to find happiness by starting a new life in another world, aiming for a stable life and a happy family. But things didn’t turn out the way he expected…