More than 200 Allied aircraft crashed in northern Australia during the Second World War, and some are still missing with no survivors and no witnesses left to say where they went down. Marine explorer Ben Cropp has found the sunken wing of a four-engine bomber resting beside a coral reef, and this film follows his team back to the site to work out which aircraft it actually is. Divers survey the wreckage, measure and photograph the wing, and cross-check details against wartime squadron records and loss reports to narrow down the possibilities. Historians and researchers weigh in on which bomber types operated in the area and what happened to their crews, turning the dive into a piece of detective work as much as an underwater expedition. The stakes are personal as well as historical: identifying the plane could finally account for airmen who have been missing for eight decades, giving their families and service records a definite answer after decades of uncertainty.