(2+5: Missione Hydra)
The Professor Solmi, an eminent specialist of nuclear technologies is in charge of inquiring on a strange phenomenon that produced in the region of Molino, where a UFO has been observed a few time ago. A radioactive task that spreads on the ground leash to guess the presence of a underground excavation suddenly revealed thanks to an earthquake. Accompanied by his daughter Louise, his assistant Martin Baldi and two engineers, the Professor Solmi climbs down to explore the gulf. There, they discover a spaceship...
Joint by oriental agents who came to hoard their discovery, earthlings are made captive by two aliens, Ben and Hart, under the commandment of Phena, a pretty creature. While they were in recognition mission to evaluate atomic risks fathered by residents of the Earth, the spaceship of the visitors buried in this crevice. Phena orders the Professor Solmi to do everything possible to repair a defective piece of the main thrust of the vessel that prevents them to leave back. To constrain him to archieve this mission, Phena keeps Louise in hostage.
The Professor Solmi and Martin return with the mechanic repaired. But the aliens have received the order not to deliver their prisoners but to drive them on their planet Hydra in order that they do not give the alert. The spaceship takes off. Knowing that they will never see their planet again, earthlings mutiny and take the ship's control. In the fight, a bullet touches the computer and provokes the spaceship to drift. In a common effort, they succeed to balance the engines avoiding to crash on an unknown planet on which they hardly land...
Spoiler ! the end of the story is revealed below…
The place serves them for convalescence and love sentiments tie between earthlings and residents of Hydra. As Hydra does not reply to their calls, all except Phena decide to return on Earth. Their decision is all the more quickly taken that they have to escape as a horde of tribal creatures attack them.
On route to the Earth, they meet a terrestrial spaceship, certainly Hungarian origin. When they approach it, they understand that years have passed on Earth since they leaved and that the blue planet was victim of an apocalyptic nuclear conflict. A disaster that they observe by themselves when they land. Because of the important radiation that rules there, they have to leave back. The ship takes off again and Phena puts the cape on Hydra. What she discovers there is no more rejoicing. Residents of the planet have escaped because of the unbreathable becoming atmosphere leaving behind them some inhabitants who welcome them. Together, the survivors of the two worlds are going to start a new life.