Gates travels to the D-Day battlefields and the beaches of Normandy where he joins investigators making history-changing discoveries about the Longest Day. Josh explores alongside military historians using cutting edge technology to uncover shocking secrets about the invasion, including a never-before-discovered complex of Nazi bunkers as well as an unexploded bomb frozen in time in the waters off Normandy's coast. Josh's in-depth investigation reveals forgotten mysteries surrounding the most important battle in modern history.