"I think we are going a hundred miles an hour into a brick wall and nobody seems to be paying much attention." This is how one scientist describes the urgent necessity of providing the world with a clean, safe and inexhaustible source of energy. Heads of state are bickering over climate agreements, electric cars are turning out to be less green than we thought, and consumption is still the engine powering Western society. Meanwhile, an international group of scientists at the Cadarache research and development center in the south of France are working on constructing the ITER (International Thermonuclear Experimental Reactor), a kind of artificial star that will eventually produce a lot of energy using nuclear fusion. To make the complicated process of nuclear fusion (not to be confused with nuclear fission) easier to understand, the makers of this attractively designed and extremely well-documented film make use of an effective range of tools: infographics, archive footage, historical overviews, animations and several interviews with enthusiastic scientists. Let There Be Light examines the ITER phenomenon from all possible angles: as a scientific triumph and a technological challenge, but also as a costly undertaking and organizational monstrosity in which each participating country tries to safeguard its own interests.