After losing his job, Law's character is given information concerning a large stash of gold in a sunken Nazi U-Boat. So he assembles a crew to help man the submarine and extract the gold. The trouble is there are tensions between various members and that puts everyone at risk.
These types of gold-hunting thrillers are, as one might say, a dime a dozen. I've seen similar films many times before, in a variety of settings too. And 'Black Sea' doesn't want to stray from the formula. That, coupled with the lack of any meaningful character development, means that the film lacks suspense or real investment as it is all spelt out from the start. You know what will happen, how it will happen, and who will be involved. And, in all honesty, the characters in the film really should know that too.
However, these kind of films can provide throwaway entertainment. This did keep my attention and made the near-2-hour runtime go by fairly quickly. And it was adequately made, though apparently not well enough to make it more than the ultimately generic, throwaway film it is.