In the film Rymdresan, we follow 12-year-old Mariana and her stepbrother Marcus, who after a fight end up on a home-built rocket. The one behind the rocket building is the crazy scientist Albert and his sidekick Lemming, a talking lemming. The unlikely quartet embarks together on a fast-paced journey back in time to prevent a rocket accident that took the life of Albert's great love Lisa. The journey takes them to Mars, where they are faced with a crucial choice: Should they save Earth or Albert's great love? Rymdresan is a light-speed family adventure about friendship, science, and the importance of believing in yourself. The film is based on a children's book by astronaut Christer Fuglesang.