Coming from the very far planet Hydra, a starship with engines failure crash-lands in the subsoil of Sardinia.
A short time later the whole territory around parches in an inexplicable way so that the institute of geology commissions scientist Solmi with doing an inspection.
The scientist arrives on the place with his assistants and his daughter Luisa.
After being reawakened from a long and voluntary hibernation, the alien crew commanded by a very beautiful woman called Chaena captures the professor and his team and first forces the earthmen to repair the spaceship, then kidnaps them and takes off again to their home planet.
During the voyage a friendship is born between humans and aliens, but after the meeting in space with a Soviet starship alarming news are divulged.
The alien ship comes back to earth and all will discover that our planet has been destroyed by a terrible atomic war.
The earth survivors are taken to Hydra which they will elect as their new residence in the hope of creating a better race than the one which has destroyed its own home planet.
The movie was made on an extremely low buget in those days (it was 1966) and the special effects are very simple, but to see this movie again today is a little bit touching and even some ideas in the plot are really interesting.

For the score no expenses were spared and it was put into the hands of Nico Fidenco.
This CD project which has been supervised by M° Fidenco himself has been possible thanks to the monaural mastertapes preserved in the C.A.M. archives.
The OST has been performed by a big orchestra conducted with gusto by Roby Poitevin and by the choir of I Cantori Moderni di Alessandroni, and during the session also many strange Alien sounds were created for the beings coming from planet Hydra.
The author has written a romantic and dance floor motif as main theme for orchestra and choir which would perfectly fit into a spy movie like those of Our Man Flint and Matt Helm and which is introduced in Titoli Di Testa (Tr. 1), reprised as GoGo music (Tr. 3), with an exciting orchestral Bossa (Tr. 4), an organ Bossa (Tr. 6), as a slow version (Tr. 9, Tr. 22), a Bossa with celesta (Tr. 13) and with steel guitar (Tr.25) and in the stunning Finale (Tr. 26).
The whole dramatic side of the story placed in space and aboard the spaceship from Hydra is underscored with orchestral and electronic passages which illustrate the encounter between humans and aliens (Tr. 1, Tr. 8, Tr. 11, Tr. 12, Tr. 14).
Fidenco has also written a Beat-Mod theme which reflects the music of that period and which we can hear in Tr. 5, Tr. 17 and as a love theme in Tr. 7.
In the session mastertapes we have also discovered three rare tracks in full stereo (Tr. 18, Tr. 23, Tr, 24) which describe all the beauty and the mysteries of the alien dimension and a terrifying secret which earthmen shall know.
A right and proper rescue and preservation of an OST from the Italian Silver Age and a sincere tribute to the film music of Nico Fidenco.