This movie starts off by picking up literally where the first one left off; however, after about five minutes, we have a time-skip of five years. Now the former Bricksburg (or whatever it was called) is basically a post-apocalyptic wasteland due to the attacks of the Duplo aliens. Everyone has had to adjust to a tougher life, and toughen up themselves in the process. All except Emmett, who is still convinced that "everything is awesome." However, things get crazy again when a new alien connected to the Duplo lot shows up--General Mayhem--and kidnaps most of Emmett's friends, who now must go after them and save them.
Let's cut to the chase: this movie is not that good. This is the second animated movie sequel I've seen recently which really was a huge step down from its predecessor and also went bizarrely off the rails (Ralph Breaks the Internet being the other). There are a ton of problems with this movie, some of which I can't go into very much without revealing spoilers.
First off... the plot. It does start off pretty promising with a post-apocalyptic version of Bricksburg, but once we go into space, it goes downhill from there. Like the first one, the events of this movie are basically in the imaginations of a real kid--only this time it's two kids. And this brother and sister have very serious differences on how to play with LEGOs. Those differences are solvable in real life, but in a movie, those differences are irreconcilable. I mean, how are you supposed to mix a sci-fi/post-apocalyptic adventure with an elementary girl's imagined LEGO space wedding? (Yeah, I know... they're both space-related. But trust me, they do not mix.)
But the real problem is that the movie tries to make the sister out as the victim of having her LEGO toys messed up when she tries to play with her brother... but the problem is, she actually *steals* LEGO toys from her brother. (I don't consider this a spoiler, because if you saw the first movie, you know about the events of these movies just being imagined... and it's kind of easy to see what Mayhem's capturing of Emmett's friends symbolizes.) While that doesn't justify the brother's response (which I won't reveal), I find it difficult to have much sympathy for the sister.
This is another big issue with the movie, though: there's very little subterfuge or surprise this time. Possibly because we already know that these movies take place in the imagination of children, they don't even bother trying to hide it this time. Most namely, the name of an actual LEGO apocalypse is clearly a reference to a real-world character as well. So it's pretty easy to guess what's going to happen in that regard. There are other twists that you don't necessarily see coming, but the problem is... they're not good ones. Namely in who the identity of the real villain is.
There are two more key things I take incredible issue with in this movie. First is what happens to LEGO Batman. He's quite dumbed down in this one and doesn't actually do much memorable... except do a musical number with a shape-shifting alien queen. Yes, seriously. And that's memorable for all the wrong reasons, which segues into the second other key issue I have with this movie -- there are a few musical numbers in it. I am honestly befuddled and confused as to why musical numbers (which we also saw one of in Ralph Breaks the Internet) are suddenly making a comeback. Maybe they appeal to certain people... but I just find it annoying.
After four paragraphs of explaining why this movie is really not good, you'd think there would not be much positive to say. But there are still some good moments. Probably the best part is actually the first action scene after the five-year time skip, which basically feels like a LEGO version of a Mad Max: Fury Road chase. And that's actually pretty awesome. And there are still several laughs to be had; some of them are related to the other LEGO Justice League members. Also, there's the character Rex Dangervest, and while his character is a separate can of worms, he has pet LEGO raptors... and those are cool.
But ultimately, we have another failure of a kids-movie sequel--just like Ralph Breaks the Internet, which this movie actually has a few subtle things in common with. This movie does have a certain message, and I get what it's trying to say. But it is executed so, so poorly. I'm not sure how the makers of this movie thought this was supposed to be entertaining; and heck, the laughs even generally disappear in the second half. And this is all the more bizarre because the first LEGO Movie was inventive, surprising, and generally a joy to watch. The only thing of those that this movie is would be maybe inventive. But it's possible for a movie to be inventive and still be terrible.