Mission: Impossible – The Final Reckoning is about the efforts of Ethan Hunt and his team to stop a powerful AI from taking control of the world's nuclear arsenal and bringing about the end of the world. It's also made as a deliberate, knowing swan song to the film franchise, full of callbacks to earlier films. (But don't worry if your memory of those is shaky; footage from the other films is awkwardly cut into this one to tell you anything you need to know.)
Memorial Day weekend traditionally marks the beginning of summer blockbuster season... and some would say that plot doesn't really matter that much in a summer blockbuster. It's just "grout" between the "tiles" of the big action sequences. If you (like me) don't subscribe to that way of thinking, there's definitely going to be a low ceiling on how much you can like The Final Reckoning. The plot of this film is pretty bad on more than one level.
First is how shockingly complex it is for how minimal a role it's supposed to play in the movie. Although the movie is nearly three hours long, there are essentially only two major, elaborate action sequences in it (and depending on how you'd count it -- that is, whether a simple shoot-out or fist fight pegs the needle for you -- one to four minor ones). That leaves a lot of time for talk, which is crammed-to-bursting with exposition about "the Entity," its plan to take over the world, and the way it can be stopped. For as much time as they spend talking about all this, you'd expect the Evil Plan to make more sense. Instead, a lot of that time goes to having characters awkwardly explain why the Entity isn't doing the more obvious thing that would be a whole lot simpler (and probably reduce the overall movie runtime to two hours).
More unforgivable is the way this part two completely abandons the thing that was most compelling about part one. The Mission: Impossible films have always had an undercurrent of distrust: never believe what you see, because at any moment, someone could tear off a realistic head mask and reveal themselves to be someone completely different. Dead Reckoning Part One upped the ante on that idea by presenting an enemy that could masquerade anywhere in cyberspace. Against the Entity, you could trust nothing connected to a digital source. The Final Reckoning makes passing mention of this threat on a couple of occasions, but never actually uses it in any meaningful way. Here, the most distinct "villain" in the history of the franchise abandons all subterfuge for a boring, brute force scheme.
But say you are one of the "who cares about the plot?" crowd. Are the action sequences you're really here for worthwhile? Sort of. There's no denying that the final, climactic stunt -- an extended aerial chase between biplanes -- is thrilling. If this is truly the last big stunt in the last Mission: Impossible movie franchise, then it's everything you want. And it effectively one-ups the last time Tom Cruise hung off an airplane for these movies. (The movie knows this, which is why it isn't afraid to show you an early flashback clip reminding you of that stunt.)
The big stunt in the middle of the movie is an extended underwater sequence inside a downed submarine. And unfortunately, it's far less satisfying in a number of ways. This seems more a triumph of clever set design and camera work -- important components of a good action sequence, to be sure, but not the "watch Tom Cruise do insane things" promise at the heart of this franchise's best stunts. Although the scope is massive, the impact is less impressive than the previous underwater stunt in the franchise -- also in Rogue Nation. (And again, the movie seems to know this; unless I missed it, it doesn't show you a clip from that sequence in this movie.) Most disappointing is the way Ethan Hunt escapes his situation at the end of the sequence, by doing something we're expressly told can't be done when the whole premise is set up. Despite "impossible" being in the name of these things, it feels like the missions are usually merely "implausible."
The resolution of a cliffhanger is rarely better than the cliffhanger itself. Mission: Impossible – The Final Reckoning is not an exception to that rule. And since I gave Part One a B-, it feels about right to me to give this movie a C+.