Adapted from a novel from sci-fi series by Kyr Bulychev about a little girl Alice. It's Alice's birthday and as a present she is invited by an old alien friend archaeologist Gromozeka to join him on an expedition to an alien planet Coleida which population was destroyed by a space plague a hundred years ago. Arriving at the planet they decide that Alice, using a time-traveling device, will go back in time to the day when the plague was brought in by their space expedition to try and save the planet from destruction by spraying the astronauts with a vaccine. To achieve that, she and another alien scientist professor Rrrr, who looks just like a cat, must make a long and perilous journey to the planet's spaceport.