摄影师工藤太郎在坐飞机的途中发现一架太空囊坠入大海,那正是4个月前离奇失踪的无人木星探测器赫利俄斯7号。回国后的工藤接到陪同开发公司调查队前往塞吉欧岛的工作,而塞吉欧岛正位于赫利俄斯7号坠落地点的附近…… 另一方面,塞吉欧岛突然出现巨大的怪兽,这一切似乎和赫利俄斯7号有关……A space probe is infiltrated by alien beings and then crashes on a remote Pacific atoll. A group planning to build a resort hotel land on the island and discover it to be inhabited by giant mutant monsters created by the aliens in an attempt to conquer the world.