Robinson (Jude Law), a veteran captain of under-sea salvage, loses his job in a redundancy. His friend Kurston informs him about a German Type VIIC[note 1] U-boat from World War II that sank off the Black Ocean with a cargo of gold worth millions and asks him to participate in the secret expedition to recover the gold. But when greed and desperation take control onboard their claustrophobic vessel, the increasing uncertainty of the mission causes the expedition team to turn on each other to fight for their own survival