Yoichi Tsuitenai was considered the unluckiest boy in his hometown. That changed one day when his luck finally ran out, resulting in his death after being crushed by an alien spaceship. However, during this critical moment, he was found by Luckyman, the great hero of the cosmos, who fused with him. This fusion granted Yoichi the power to transform into the universe's luckiest superhero. Now, as Luckyman, Yoichi must defend Earth from aliens who are invading to conquer it.