Framed five years ago, brilliant ex-captain Erin is reduced to a bullied crewman, while her traitorous ex-fiancé Lucas steals her glory as a celebrated navy hero. When their submarine hits a deadly minefield and faces endless life-threatening malfunctions, incompetent Lucas nearly kills everyone time and again. Undercover secret agent Kane knows the truth of Erin’s frame-up. He stands firmly by her side, takes over the vessel and lets Erin lead the crew to escape enemy torpedoes. The whole submarine regains faith in Erin and calls her captain once more. Consumed by jealousy, Lucas fabricates evidence to brand Erin a traitor. Kane is ready to fight anyone to protect the woman he loves.