The Jacket is a film that you really have to buy into in order to enjoy. If you cannot accept the basic premise — a man travels forward in time in order to learn information which will alter the future for the better by telling it to people in the present — then you will laugh it all the way to the shame shelf. However, if you do buy in, what you get is a thought-provoking little movie that contains suspense, intrigue and a couple of very fine performances.

Adrien Brody takes the lead as a man named Jack, a soldier who almost died in Vietnam after trusting a child who happened to have a gun hidden behind his back. He now suffers from amnesia and delusions, and after a cop is killed, is blamed and put away in an asylum. Here, one of the doctors (Kris Kristofferson) uses a method which some would call inhumane. He puts the patient in a straitjacket, hoists them into a morgue drawer, and leaves them there for a few hours. It’s in this drawer that Jack begins to travel forward in time, meets a woman named Jackie (Keira Knightley), and starts to change the future.

It’s important to note that, before being put in the mental facility, he met Jackie when she was just a child. He helped her and her mother (Kelly Lynch) start their car. In the future, Jackie isn’t a little kid anymore, although she still remembers the day in which Jack stopped to help them out. Jack’s main goal now, especially after learning that he will die, is to improve Jackie’s life, and the lives of those around him. And if he can prevent himself from dying, that would probably be good, too.

See how, if you don’t take it seriously and for what it is, this is a very silly and laughable premise? You have to buy in or the film will be laugh-fest. The time travel element isn’t exactly the silliest magic that can happen in film, and it’s actually more believable than some of the other things we sometimes see, but you have to believe in it here or the film won’t work for you. When you do, you start thinking about how it works, and whether or not any paradoxes occur because of it (hint: they do).

What doesn’t really work is the relationship between Jack and Jackie. Jack meets her when she’s a little kid, and then sees her again a good 15 years later. She initially dismisses him as a crazy person, but the second time he time travels, she’s instantly accepting. And then they become lovers, and she can’t stand to be without him — and he to her — and it gets even sillier than the time traveling aspect. I didn’t believe in that part of the story, and it kind of ruins the rest of the film.

See, pretty much all of Jack’s actions from the time that the characters fall in love stem from his desire to figure out how/why he’s going to die, and to improve Jackie’s life that he has to accept she’ll have to live without him. He essentially wants to use information from the future to change what will happen. Hindsight is 20/20, right? So that’s what he does, and it’s difficult to root for him because you can’t invest in that relationship.

Granted, they both seem like nice enough people, so at least they have that going for them, but there’s no feeling of their relationship being genuine. She’s a damaged soul who might just be attaching herself to the only person who was ever nice to her, and he seemed to develop something with her when she was just a kid, which is creepy. This is why time would help to make it feel more real. As it is, it’s a romance built on potentially awful characteristics, and is not something that you want to cheer for.

The odd thing about The Jacket is that it manages to create a sense of suspense even though there’s never a whole lot going on. There’s a unique style that it has which helps — director John Maybury creates an impactful visual look to his film — but even as the story goes on, each scene has something that could build and explode. And Jack only has a certain amount of time when he is in the straitjacket, so that time limit could always run out. It’s not really a thriller in any conventional sense, but it’s a fun, thoughtful little movie.

Adrien Brody, coming off his Oscar-winning role in The Pianist, has gloomy down to a science. That’s what he is for the longest time here, although he also gets to smile and laugh and have a good time — when he’s with Keira Knightley, that is. She, trying out a convincing American accent, is strong as well, although despite being billed as a top actor is only in a handful of scenes. Kris Kristofferson, Jennifer Jason Leigh, Kelly Lynch and Daniel Craig round out the pretty impressive supporting cast.

The Jacket is a fun movie that only stops being so once you start thinking more about its characters and their relationships. The time travel aspect is enough to distract you for the majority of the time the film plays, and if you stop trying to think too deeply about it once it finished, it’ll remain in your mind as a fun little diversion, but not a whole lot more. It has a strong cast, a unique style, and contains more suspense than it should, and if you’re asking me, I say to give it a watch.