Chopra is a cloud of particles and dust that was created by a falling comet. When Czech astrophysicist Jakub Prochazka is asked to undertake an eight-month mission to explore it he agrees, because he wants to answer many of the questions that he and his fellow astrophysicists have about it. What is it exactly? Why did it come to exist? Chopra has been turning the sky purple at night. There are many factors about Chopra that make the mission dangerous, and the Czech Republic is the only nation willing to send its scientists to collect samples of the dust cloud.
Jakub quickly becomes a celebrity because of the mission. Jakub has an ulterior motive for undertaking the mission. He is not really interested in becoming an astronaut. What interests him is changing the way he and his family are viewed in Czech society. His father had been a high-ranking member of the communist Party and committed a great many wrongdoings, for which Jakub and his grandparents were punished. Becoming a new hero in the eyes of his countryfolk appeals to Jakub.
While on Chopra, Jakub has contact with his wife and with his mission engineer Petr but his wife feels abandoned and leaves him. Jakub turns to alcohol and begins to hear voices, wondering if he is losing his mind. He is convinced he is having a breakdown when he sees a large talking spider on the spacecraft. The spider tells him he is from another planet and has come to research the humankind of earth.
Jakub hires a spy to follow his estranged wife, Lenka and passes the time chatting with the spider whom he names Hans. As they near Chopra the particles of dust tear up his spacecraft and Jakub is convinced he is going to die. He is rescued at the eleventh hour by a Russian spacecraft. The cosmonauts on board are part of a secret mission. They will be arrested when they return to earth. One tells Jakub that he has met Hanus too. Jakub and the cosmonauts decide to try to escape, but their attempts crash the Russian shuttle.
The cosmonauts are killed but Jakub survives although it is announced that he is also among the dead. Jakub decides this is probably for the best and will enable both himself and Lenka to make new lives. He returns to the place where he grows up, and settles there, living a quiet life.
