Aliens from the constellation Hydra crash-land on the island of Sardinia. A prominent scientist, his daughter, several young technicians, and a pair of Oriental spies are taken hostage by the beings so they can use them to repair their spaceship's broken engine. With that done, they take off towards their home planet, taking the earthlings with them. However, the humans attempt to mutiny against their captors, inadvertently sending their tiny spaceship hurtling into the infinite beyond...

來自外太空的不明飛行物體墜毀在莫斯科，目睹過程的人們，有的人決定逃命為上，有的人決定大膽與外星人進行親密接觸，而更多的人決心殊死一戰，外星生命與人類之間的戰火一觸即發……

在外星飛船墜落莫斯科事件3年後，獲得外星力量的少女尤莉亞成為政府祕密實驗的研究對象，不僅人類覬覦她的能力，就連外星異種也亟欲取回她這股足以毀滅世界的力量。在雙方追殺之下，少女不得不作出選擇決定自己該為誰而戰……