Diner owner Al Templeton reveals a time portal to October 21, 1960 in his closet to his friend, English teacher Jake Epping. Dying of cancer, Al asks Jake to travel back to the 1960s and prevent the assassination of United States President John F. Kennedy. Al explains his own past attempts and mistakes to Jake to stop it, noting his apparent onset of cancer was from spending extended time in the past. Armed with Al's research, Jake goes to 1960 and surveils a Kennedy intimate, believed to be Lee Harvey Oswald's handler. He finds that the past is "pushing back" as accidents and incidents make it difficult for him to achieve his goals. He returns to his lodgings to find them burning, Al's notes nearly all destroyed, and the landlady's son dead. He decides to give up, and "return to Maine", but stops to try and prevent a multiple murder he had heard about in the present.