When this movie begins in the middle of an over-the-top prison riot in Bangkok that leads to a crazy "Shawshank Redemption" joke, it's the first sign that "The Hangover Part III" is not just business as usual.

The first film, written by Jon Lucas & Scott Moore, featured a very clever hook, and when Craig Mazin, Scot Armstrong & Todd Phillips wrote the script for the second movie, they mirrored the structure of the first film closely. When I spoke with Phillips recently, it was obvious that he loved the reaction of people who were bothered by that, and at first, he and Mazin evidently flirted with the idea of making the third film yet another riff on the same structure. Thankfully, they tried something different this time, and while it may not recapture the exact same giddy thrill as the first film, this film manages to clarify what the overall story of the trilogy is in a way that I found satisfying and quite fitting.

The film opens with Alan (Zach Galafianakis) at his manic worst, driving along a freeway towing a trailer that holds a full-sized giraffe. His joyous song of "I love my life!" had me laughing right up to the moment he does something terrible, leading to a "Final Destination"-like incident that leads to a scene with his father Sid (Jeffrey Tambor) dropping dead in a moment that's played for both laughs and real sorrow, which seems to be something that interests Phillips this time around.

When Phil (Bradley Cooper), Stu (Ed Helms) and Doug (Justin Bartha) show up at Sid's funeral, it is obvious to them that Alan is out of control. Over the course of the first two films, this has been one of those givens. Alan has always been a spoiled rich kid whose obvious psychological problems have been played for laughs. This time, though, it seems like Alan is going to continue to spiral out of control unless something is done. He has no respect for his mother, so she can't convince him to get help. It's up to the "Wolfpack," the friends he tormented in the first two films, to take him to a facility where he can get the help he so desperately needs.

On the road to that facility, they are run down by a truck and taken to meet Marshall (John Goodman), who is looking for Chow (Ken Jeong), the lunatic who they tangled with in both of the previous films. Chow was the one we saw breaking out of prison in the film's opening sequence, and this time around, he is the antagonist who keeps the film's plot in motion. He's the chaos that keeps causing problems for the guys no matter what they do, and the guys have to hunt him down for Marshall, or he promises to kill Doug, who once again finds himself sidelined during much of the action.

There's a fairly major detour to Tijuana and rural Mexico before the film finally makes its way back to Vegas, which seems inevitable. While I feel like the first two films were all about the way our actions have consequences, this final film is all about Alan having to learn to exist as a self-sufficient human being, and it gives Galifianakis his most fully-realized role to date. He reveals the dangerous sense of humor that drives Alan even as he also finally starts to make a case for some real growth. There are two sequences in particular that aren't particularly funny, but that reveal just how deeply Alan's desire to find a connection really runs. One involves the baby from the original film (played by the actual kid who was one of the three infants used in that movie) and the other involves Cassie, a new character played by Melissa McCarthy. Galifianakis makes choices that seem to come out of left field, approaching each moment in ways that I found unsettling at times, funny at other times, but always interesting.

At this point, i'm not even sure I think "The Hangover" series is particularly hilarious. I'm just intrigued by it as an ode to the way we allow ourselves these moments of excess, and what it is that we keep bottled up inside of us except in those moments. Stu, the character played by Ed Helms, seemed genuinely upset by his own inner urges in the last film, and at one point, he declared "I've got a demon in me." We all do, though, and the only question is how well we keep it under control. These guys all seem willing to let it off the leash at times, no matter what the final cost, and in this film, Alan finally learns that he can't live like that at all times.

Ken Jeong's performance is part con man, part crazy person, part puckish imp, and he tears into every scene in a big way. At one point, we follow a few characters into a Vegas suite that Chow has taken over and turned into a "party," and it's played as dark as the moment where Martin Sheen first finds Col. Kurtz in the jungle temple. Even so, there are signs here that Phillips isn't all about nihilism. There are several scenes where we catch up with past characters and see that they've actually done well for themselves, and I appreciated those moments because they temper the otherwise jet-black view of humanity that Phillips has.

At this point, I have to give extra credit to Lawrence Sher, the film's cinematographer, because so few comic filmmakers are willing to use widescreen, and all three of these films have made great use of the full scope frame. Tech credits are strong across the board, and consistent with the first two movies. As with the other films, you need to stay once the credits begin because there is a moment that comes in the middle of the credit sequence that is flat-out deranged, as freaky as anything else we've seen in the series, and it suggests that while Alan may be better than he used to be, nothing is ever going to fully heal these lunatics.

I'll be curious to see what the general public makes of this one. It feels to me like the right way to round out the series, but it's such a different film in many ways that I have no idea if people will respond to it or not. I think they managed to redeem the series with this last film, and it strikes me as a very strange take on the story so far. Todd Phillips will no doubt continue to mine the darkness we all have inside of us for laughs in the future, so it's good to see that when it comes down to it, he has a soft spot for his own characters, and he does ultimately give them all some small bit of solace, even if they seem determined to piss it away in the film's final images.

"The Hangover Part III" opens everywhere on Friday.