A team of dedicated divers and researchers embarks on a mission to locate the wreckage of a German U-boat, the U-479, in the Baltic Sea. As they navigate the challenging environment of the Finnish archipelago, they uncover the stories of other sunken vessels, including the Vrouw Maria and the Park Victory, while grappling with the logistical and physical demands of technical diving. The film captures the camaraderie and shared passion of the team as they explore these underwater historical sites, highlighting the delicate balance between preserving maritime history and the inherent risks of their pursuit.