Fasten your seatbelt and get ready for a pulse-raising journey to alternative history. December 1944. The end of the war seems to be in sight and the Allies are confident of victory. Then comes a catastrophe that no one can believe. John 'Cowboy' O'Hara, the pilot of a BOAC airliner, is ordered to carry out a dangerous mission to deceive the enemy - a mission so perilous that he and his crew may never return home. Soon after the takeoff, they begin to suspect that there is an enemy spy on board. The spy's sabotage attempts get more and more ingenious, leaving the crew fearing for their lives. But who is the saboteur and can the crew catch him - and complete their mission successfully - before it's too late?