2023, Florida. Duncan Ainsworth, a former USAF pilot going through a rough patch, is recruited by Blek Industries to test a new, highly experimental hypersonic flight system. The test flights are to be conducted with Lucie Delosnier, the French scientist in charge of the system and a thorn in his side, as his copilot. Unfortunately, early in the test phase, they lose control of the airplane and go through a strange zone of turbulence only to re-emerge in the skies of war-torn France in ... 1917!