Every day, nuclear power plants spread over the entire world create large amounts of high-level radioactive waste and no one knows what to do with it. Therefore, barrels filled with this waste are placed in interim storages, which are vulnerable to natural disasters, man-made disasters, and societal changes. In Finland, scientists are working out the world's first permanent repository, which will be hewn out of solid rock - a huge system of underground tunnels – and which has to hold out for at least 100,000 years, as this is how long the waste remains hazardous. Once the waste has been deposited and the repository is full, the facility is to be sealed off and never to be opened again. The scientists have taken account of climate changes, natural disasters, human forgetfulness and, above all, the unpredictable human curiosity. How do they prevent future civilizations, just like ours, from opening this mysterious construction? A delightful film about deadly serious questions.