The story narrates the adventures of two children, Berenika and Jurek, who get lost in the Silesian Park. Wandering among the trees, they stumble upon the Silesian Planetarium, whose building transforms into a gigantic spaceship. On their journey towards the titular comet, the children are accompanied by Nicholas, who tells the Planetarium's passengers about constellations, planets, and other celestial bodies. Observing the comet in the sky encourages the children to embark on a distant journey and see it up close.