The film begins with David Filby arriving at the home of H. George Wells for dinner. He is joined by other colleagues, but George is late. He soon arrives in disarray as he has traveled back from the future. We learn that George has invented a time machine, an idea that most of his colleagues find to be ridiculous except for the fact that it could make him some money. However, George has created it in order to control his destiny, even stop war. David attempts George to destroy the machine, but when George is alone he uses the full scale version for the first time.
He travels from the year 1899 in London to 1917 where he meets David's son, learns of World War I with the Germans and that David has died in the war effort. He begins his journey once more, this time stopping in 1940 during the World War II air raids in London, war is on once more. He then travels to 1966, when everyone is running underground as an atomic bomb is about to be dropped on London, which destroys the entire city, which is then rocked by a volcanic eruption which pours lava out upon the city. George narrowly escapes and sets course to 800,000 years into the future; this is when the city has ceased being encased in the hardened lava. He finds young people living in a vibrant earth. Despite their apparent prosperity, they have become mere food for the Morlocks, which are men who have devolved so much they have resorted to cannibalism. The Morlocks use bomb sirens to lure the other human beings underground so they can eat them.
George has met a young woman named Weena in this time period and attempts to save her and the others from being eaten by the Morlocks. He is able to fight them off with fire and force and eventually the others join him to defend themselves and burn down the Morlocks shelter. George is able to find his time machine and return to the future, but without Weena.
Once he is back in 1900 London no one except David believes he has just traveled into the future. Desperate to live in a time where he matters, George uses his time machine once more when his colleagues all leave. David attempts to stop him, but is too late. George has traveled back to Weena, and David is unsure if he will ever see his friend again.
