The sun and other stars generate energy. In the sun, a fusion fire burns in a huge ball of plasma. Here, hydrogen nuclei fuse to form helium. This releases a lot of energy. Fusion research is attempting to replicate these processes here on Earth. This endeavor is being led by the ITER mega-project, an international collaboration worth approximately 20 billion dollars. Some 5,000 people active in science and technology and hailing from all around the globe are working on ITER. Together, they are working on a gigantic puzzle consisting of more than a million components. Research into nuclear fusion has been ongoing for decades. But so far, it has proven incredibly difficult to carry out nuclear fusion on a scale that ultimately produces more energy than is needed to initiate fusion. In the sun, heat and pressure force the fusion of atomic nuclei. On Earth, there are two methods for this: magnetic and laser fusion. Along with a major German project, W-7X, a new wave of start-ups are vying to be the first to produce clean, inexhaustible energy. The film explains how nuclear fusion works and what role it could play in the European energy landscape, the challenges involved, the difference between fission and fusion and whether this just might be the solution to humanity's hunger for energy.