Shipwreck survivors found on the presumably uninhabited Infant Island leads to a scientific expedition that discovers a surviving native population along with the Shobijin, tiny twin fairy priestesses of the island's mythical deity called Mothra. After the fairies are kidnapped by an exploitative businessman named Clark Nelson, Mothra sets out to rescue them.

Nuclear tests create a radioactive man who can turn people into slime.

Two scheming ne'er-do-wells find a lost nuclear weapon in the ocean near Los Angeles. They decide to light-heartedly try and blackmail the city by asking for money from each citizen. This arouses the attention of the local authorities.