Yoichi Tsuitenai was the unluckiest boy in his hometown. Until one day, his luck truly ran out when he was crushed by an alien spaceship, killing him. But, in this time of need, he was discovered by the great hero of the cosmos Luckyman, who fused with him giving him the power to turn into the universe's luckiest superhero. But now Yoichi, as Luckyman, must defend the Earth from aliens invading to conquer it.