Monster From A Prehistoric Planet

A team of explorers searching for exotic wildlife unwittingly release a horrific force on Japan. Refusing to heed the natives' warnings, they return from a South Seas island with a strange triphibian creature. Plans to use Gappa as a tourist attraction are derailed when the monster's vengeful parents descend on Tokyo. Laying waste to entire cities in the pursuit of their offspring, the giant monsters are unaffected by modern weaponry. As the island prepares itself for total annihilation, scientists rally with a daring plan to reunite the creatures and preserve humanity...