Plot is set in Chicago, where the group of top scientists led by Dr. Alistair Barkley (played by Nicholas Rudall) tries to create cold fusion - process that would turn water into cheap and economically viable source of energy. Their efforts don't yield any result until Eddie Kasalivich (played by Keanu Reeves), young undergraduate student of machine engineering, applies some of his ideas. With cold fusion finally becoming reality enthusiastic scientists want to share their discovery with the world, but some powerful people in US government don't think this is such a good idea. They prevent the leakage of the story by attacking the laboratory, killing Dr. Barkley and planting explosive. Kasalivich survives only to discover that he is framed for murder and espionage. Kasalivich and young physicist Dr. Lilly Sinclair (played by Rachel Weisz) become target of nation- wide manhunt, led by FBI Agent Ford (played by Fred Ward). Their only hope is Shannon (played by Morgan Freeman), mysterious project manager with agenda of his own.

CHAIN REACTION is something very rare in modern Hollywood - action movie with the script that tries to tackle important world issues with a semblance of intelligence. While other Hollywood screenwriters would use "cold fusion" as nothing more than cheap gimmick, CHAIN REACTION screenwriters try to speculate about the effects this discovery would have on real world. In their opinion, discovery of cold fusion would result in re-alignment of world economies, recession and complete tilting of power balance in USA and world as a whole. Or at least, that is how Powers That Be would approach this issue and why the knowledge of cold fusion would be suppressed.

This speculation is, unfortunately, the only intelligent thing in a movie that didn't take anything else seriously. The casting was dreadful, with Keanu Reeves being as convincing in his role of scientific genius as the scene that features him outrunning nuclear explosion with motorcycle. Rachel Weisz is wasted in thankless role of unnecessary female character, while even such dependable British actor like Brian Cox disappoints in the role of villainous CIA agent with Southern accent. Director Andrew Davis uses the script as an opportunity to stage few interesting action scenes, but many of them owe too much to THE FUGITIVE, Davis' previous (and much better) effort. The greatest problem is confusing script with villains not knowing whether to permanently silence the protagonist or to get him alive and thus obtain his precious knowledge. CHAIN REACTION might had interesting idea behind it, but the execution was utterly disappointing.