Story

Infant Island, a solitary isle floating in the far southern waters, was a paradise where people lived peacefully...

The natives of the island regarded Mothra as the island's guardian deity and cherished the Shobijin as messengers of love. One day, though, the peaceful Infant Island was attacked by the Xilien who are plotting to conquer the Earth. As part of that plot, the Xilien abduct the Shobijin in order to use their supernatural abilities to help in conquering Earth.

The people of the island continued to desperately pray. "Mothra, our precious Shobijin have been kidnapped. Please rescue them and protect the peace of Earth!"

The prayers of the natives are answered as now Mothra has risen. She is attacked, though, by monster after monster that are controlled by the aliens. Godzilla, Minilla and Rodan are all enemies by manipulated by the extraterrestrials.

In order to rescue the Shobijin and protect peace on Earth, Mothra leaves Infant Island, crosses the ocean where powerful enemies lurk, and heads to Tokyo where the aliens have made a secret base in order to conquer Earth. However, the only way to stand up to King Ghidorah, who is under Xilien control, is for Mothra to create a cocoon and become an adult. Then, when Mothra becomes an adult, she can finally fight against King Ghidorah in their innermost sanctum...

[story translated from the booklet]

Mothra

Players take control of Mothra and start the game with two spare lives. If Mothra's life bar is completely depleted and she has a spare life Mothra will re-materialize from where she died and all enemies on the screen will be destroyed, with the exception of environmental hazards like the volcanoes.

Mothra begins in her larval stage and won't evolve into her imago form until late in the game.

Controls

The joypad is used to move Mothra across the stage. She can move in any direction, including backwards.

1: Webbing
Mothra's only hope at keeping the other monsters at bay, the webbing will cause enemies to freeze for a short time after being hit, with the exception of Godzilla and Hedorah. If used enough, the webbing will defeat other monsters. Mothra's webbing can be fired in all directions, except downward.

2: Power Ball
Mothra can fire a concentrated blast of webbing, which deals additional damage to enemies. This move is limited, with a number appearing in the lower right showing how many Power Ball shots Mothra has remaining.

Although Mothra has two forms, her attacks are the same in both.

Items

1UP / Life Charge Hidden throughout the game, this power up will only be visible after Mothra shoots the area in which it's concealed with a shot of webbing. When collected it will either give Mothra an extra life or replenish Mothra's life bar.