Val Guest writes and directs this sci-fi drama. After global nuclear testing knocks the world off its axis, temperatures begin to rise rapidly as the planet is sent careering towards the sun. In London the heat is causing the Thames to dry up as baffled Daily Express reporter Peter Stenning (Edward Judd), his colleague Bill Maguire (Leo McKern), and his girlfriend Jeanne Craig (Janet Munro), resolve to get to the bottom of the matter. After battling the Government for the truth, they are shocked to discover the fate of their planet and must search for a solution before it's too late.