Flight Lieutenant (actually Second Lieutenant) William Terrance “Terry” Decker of 56 Squadron Royal Flying Corps lands his Nieuport biplane on an American airbase in France, after flying through a strange cloud. He is immediately accosted by provost marshal Major Wilson, who is dumbfounded by Decker’s archaic appearance. Decker, likewise, is baffled, but by the unexplainable large modern aircraft. He is then taken into custody and questioned by the American base commander, Major General George Harper, and by Wilson. Decker snaps to attention, identifying himself as being from the UK’s Royal Flying Corps (the predecessor of the modern Royal Air Force). This puzzles Harper and Wilson. Harper, seeing Decker’s antique uniform, queries Decker if a vintage air show is nearby, or if he is making a film—Decker has no idea of what he is asked. He then asks Harper: “Excuse me sir, but where exactly am I?” Harper sardonically responds, “Where exactly did you think you were?”, to which Decker says, “Well, I thought I was landing at 56th Squadron RFC.” When asked to identify the year, Decker answers that it’s 1917. When they inform him it’s March 5, 1959, he is stunned.
Decker tells the officers his flying partner Alexander Mackaye and he were fighting seven German aircraft; Mackaye was shot down and Decker escaped into a cloud. The Americans, to Decker’s astonishment, inform him Mackaye is alive and is an air vice marshal in the Royal Air Force, a war hero from World War II who saved hundreds, if not thousands of lives by shooting down German bombers over London. The American officers add that Air Vice Marshal Mackaye, in addition to being alive and well, is coming to the base that very day for an inspection. Decker says that is impossible, as Mackaye is dead. Harper, at this time, confiscates Decker’s pistol and personal effects. Later, Major Wilson tries to help Decker remember what happened. Decker finally confesses that he has consistently avoided combat throughout his service, and that he deliberately abandoned the greatly outnumbered Mackaye when the two were attacked by the German fighters. He refuses to believe that Mackaye somehow survived against such odds.
When Wilson suggests that someone else helped Mackaye, Decker realizes that he has been given a second chance. He tells the American officer that no one was within 50 miles who could have come to Mackaye’s aid, so if Mackaye survived, it had to be because Decker went back himself. Knowing he cannot have much time to go back to 1917, Decker pleads with Wilson to release him from custody. When Wilson refuses, Decker assaults him and a guard and hurriedly escapes (without his badge and personal items). Running outside, he locates his plane, punches a mechanic who tries to get in his way, and starts the plane’s engine. He is about to take off when Wilson catches up and puts a pistol to his head. Decker tells Wilson he will have to shoot him to stop him. After hesitating, Wilson allows him to escape and Decker flies his plane into white clouds and vanishes.
Wilson is rebuked by Harper for believing such a fantastic story and for allowing “that madman” to escape. When Mackaye arrives and takes a seat, and Wilson asks him about Decker, he says “Oh I certainly should know him—he saved my life.” Mackaye proceeds to recount how Decker and he were attacked by seven German aircraft while out on patrol. Decker, in his fit of cowardice, flew away, disappearing in a cloud, with Mackaye thinking at first that Decker had abandoned him. Suddenly, Decker came diving out of the cloud with his aircraft guns blazing, and proceeded to shoot down three of the German planes before being shot down himself. With Decker’s unbelievable story now corroborated by Mackaye, Wilson comes to believe what Decker had told him. General Harper, now also beginning to believe Decker, asks Mackaye if the Germans returned Decker’s personal items, to which Mackaye responds no. Baffled, Harper then shows Mackaye the confiscated identification photo card and other personal effects of his young friend Decker, startling him. As Mackaye gets increasingly agitated, Wilson suggests, “Maybe you’d better sit down, Old Leadbottom”, shocking Mackaye further with that nickname known only to Decker and him, from over 42 years earlier. “What did you call me?”, he incredulously asks.
