There was a brief window during the run up to World War Two when Germany and Russia were trying to negotiate a non-aggression pact because both countries knew just how costly a war between them would be. Black Sea's backstory alleges that Hitler tried to sneak a clause into the pact which effectively blackmailed Stalin into paying him a shitload of gold bars, and apparently Stalin buckled and paid the ransom. However, the U-boat that was carrying the money never returned to Germany, which prompted Hitler to forget about the non-aggression pact, and once war broke out the lost gold became an afterthought... Until now, that is, when a rag-tag group of disgruntled ex-submariners have taken it on themselves to steal the gold for themselves off of the floor of the (titular) Black Sea.
That's not a bad set up for a submarine movie, and Black Sea does a reasonably good job of delivering the sort of claustrophobic thrills you would want from an underwater heist flick. The scenes where the crew members are trying to walk around at the bottom of the ocean look great, and all of the obstacles they have to overcome are logical given the naturally dangerous setting. Fans of nautical adventures will definitely be pleased with this movie.
That said, Black Sea isn't perfect - in particular the script is a little underwhelming. It spends too much time trying to create tension between the British and Soviet members of the crew in a way that felt forced and some of the characters are quite frankly unbelievable. (I get that deep sea divers are potentially unstable people, but would they really start stabbing their fellow crew members when the ship they are on is already so badly understaffed?) Fans of nuanced character dramas might want to look somewhere else, as this movie about a hunt for a lost Nazi submarine is not exactly overflowing with subtle emotional arcs.
However, while the twists and turns of Black Sea are worth discussing at length, the part that interested me the most was definitely the film's set up. The fact that the treasure they are hunting used to belong to the Nazis doesn't really matter to the characters in Black Sea - the whole Hitler-Stalin backdrop is just a plausible excuse to explain why this ungodly sum of money was at the bottom of the sea. But I couldn't stop thinking about the Nazis during this movie, because Black Sea really underscored how great they were at collecting desirable goods.
Seriously: those guys had amazing art collections. They also had amazing Biblical relics like the Ark of the Covenant. Hell, at one point they even had the keys to the gates of Hell. In Hollywood's mind the Nazis are basically hoarders, except while most hoarders are stockpiling worthless crap like newspapers and cats the Nazis were hoarding artifacts of unlimited power. If it could win a war, or make them look cultured, or just make them be generally evil, then they either had their hands on it or were trying to get their hands on it. We spend a lot of time talking about how the Nazis were not good people, but we might not be spending enough time giving them credit for being incredibly efficient at hauling swag.
All kidding aside, I'm interested in this film's Nazi-heavy backstory because its plausibility makes it a bit of a backstep from a lot of the Nazi-inspired movies that have been made in last few decades. I don't know enough about the run up to World War Two to know if the events Black Sea is referencing actually happened - I suspect the lost U-boat is invented nonsense, but still, it is easy enough to buy into its existence. That makes Black Sea very different from, say, Hellboy, because obviously the Nazis never actually had the keys to the gates of Hell.
Black Sea's believability is both a blessing and a curse. On the one hand, it requires less suspension of disbelief, but it is can also be a little underwhelming. People that find it hard to care about over the top fantasy stories will find Black Sea's piles of Nazi gold to be a refreshing change of pace from the increasingly ungrounded Nazi stories that Hollywood has been making ever since Raiders of the Lost Ark turned the Nazis into cartoon villains, but I found its mostly practical story to be a bit of let down. I know that I should be impressed that these down on their luck adventurers found a hundred million dollars in gold bricks in such a dangerous location, but while that scenario is thrilling, it is still less thrilling than finding proof that God exists and loves to melt faces.
At this point we as a culture should probably put a moratorium out on Nazi stories. I'm just not sure that there's anywhere to go from here - how do you escalate evil to the next level after it has already conquered Hell? Black Sea tried to use the Nazis to up its story's ante, but that was a mistake because their overused iconography ended up distracting from the story it was trying to tell. There are any number of reasons why a ship full of treasure might have sunk to the bottom of the sea, and I would probably have preferred most of those alternate routes over what we got. After all, there are a lot of things you can say about Somali pirates, but you can't say that they've been done to death as Hollywood bogeymen.