On April 26, 1986, a catastrophic blast blew the lid off Chernobyl's Reactor No.4. The explosion was 400 times more potent than the Hiroshima bomb, ignighting fires that burned for 10 days, sending a radioactive cloud across Europe. In the aftermath, ill-equipped workers heroically sealed the smouldering reactor in a concrete sarcophagus, but the hastily constructed shelter was only built to last 30 years. Now, 30 countries including the UK, France and the US have come together to pay for a 1.2 billion Euro international rescue plan to build a mighty 25,000-ton steel shelter which will entomb the radiation and last for a century. This documentary follows the team of international engineers as they race against time to build the structure over the disaster site.