Gaira, a humanoid sea beast spawned from the discarded cells of Frankenstein’s monster, attacks the shores of Tokyo. While the Japanese military prepares to take action, Gaira’s Gargantua brother, Sanda, descends from the mountains to defend his kin. A battle between good and evil ensues, leaving brothers divided and a city in ruins.

Society matron Mrs. Livingston Baldwin Crane is selected as a juror in the trial of former chorus girl Yvette Gordon, who’s accused of murdering her rich older husband. In court and during deliberations, Mrs. Crane proves to be a disruptive and unorthodox juror.

A singing ranch foreman (Roy Rogers) and his friend (George “Gabby” Hayes) urge a chorus-girl heiress (Dale Evans) not to sell the property.