The unicorn girl Acorna, along with other representatives of her people, the Linyari, returns home to the planet Vilinyar. Her homeland was almost completely destroyed by the Khleevi space invaders, but now the Linyari are going, with the help of their earthling friends, to restore Vilinyar. However, for this it is necessary to carry out thorough research on the surface of the planet. During these studies, Linyari scientists suddenly begin to disappear, and Acorna begins to investigate these mysterious disappearances...