rachel mcadams, about timeUniversal

Every time travel movie comes with a specific set of rules and regulations for its would-be time travelers to follow. Usually these can be quantified in numbers, like 88 (MPH) or 1.21 (gigawatts), but in the upcoming "About Time," the latest romantic comedy from British writer/director Richard Curtis ("Notting Hill," "Love Actually"), the magic number is relatively simple: 21. As in years, which is when Tim (Domhnall Gleeson) discovers that the ability to travel through time runs in his family.

Still, time travel movies typically involve a fair bit of mental gymnastics to make sense of all the paradoxes and metaphysics, which was summed up perfectly by Bruce Willis in "Looper": "If we start talking about it then we're going to be here all day talking about it, making diagrams with straws." Combine that with romantic comedy, another genre with its own strict rules, and things can get even more confusing. So, as a public service, we've broken down the rules for time travel romance according to "About Time."

It's a guy thing: Like most genetic traits, Tim's is apparently passed down from the men on his dad's side. Unlike most genetic traits, this one you might actually want to inherit.

It's a rite of passage: Having "the talk" means something quite different in Tim's family. For reasons that go unexplained, 21 is the age when said time-traveling ability kicks in, presumably so you can go back and prevent yourself from a wicked hangover. Or maybe they're just late bloomers.

There's no equipment necessary: All Tim has to do is go somewhere dark, clench his fists, and concentrate on where (and more importantly, when) he wants to go.

You have to go back to move forward: In "About Time," time travel is seemingly an evolutionary adaptation meant to solve the problem of hindsight being 20/20. Tim can't travel into the future, but he can fix past mistakes.

There's a catch: There's always a catch. Curtis' time travelers can only go to places they've been and can remember, and can only travel within their own life.

Tim can't change world history, just his own: Tim can't "kill Hitler or shag Helen of Troy," according to his dad (the always-great Bill Nighy). Instead, he's limited to an endless supply of do-overs for his screw-ups. It's kind of like starting over again from a video game checkpoint.

There's no need to bring a change of clothes: Unlike the Terminator, Tim comes back in whatever he happened to be wearing at that time. Which is freaky, but also saves him significant time beating up bikers for clothes.

Don't worry about running into your past self: It's not an issue in "About Time," maybe because it would be too complicated to explain, but mostly because Curtis really isn't interested in the metaphysics of time travel so much as its potential for sight gags.

Chase girls, not money: Tim's dad warns him against about using his newfound gift to increase his bank account. But that's not a problem for Tim, who has something much more fulfilling in mind: finding a girlfriend. Also, presumably he's already seen what happens to Biff in "Back to the Future: Part II."

Cast Rachel McAdams: After "The Time Traveler's Wife," "Midnight in Paris" and now "About Time," apparently the actress has a type. Just FYI, wannabe suitors.

The time traveler needs to be unthreatening: In order to make audiences find Tim's time travel shenanigans charming and not, you know, sleazy, you need a leading man who seems too guileless to take advantage of his powers. Enter the up-and-coming Gleeson, who gives off a distinct "young Hugh Grant" vibe. (Apparently Curtis has a type too.)

It's all about the meet-cute(s): Most rom-coms only get one meet-cute -- unless their lead is a polygamist, or in Tim's case, a time traveler. And after accidentally erasing his initial run-in with Mary (McAdams), Tim uses his powers to give himself a second (and third, and fourth) chance.

You can't make someone love you: This rule is explicitly stated, presumably to make us feel less creeped-out by Tim's time travel-aided wooing of Mary -- she must already like him. She just likes him a little more when he's able to quote her exact thoughts on Kate Moss and sweep her off her feet.

Time travel is a lot like love: In that neither Curtis nor Tim are too interested in the how or why of his peculiar ability, or how a girl like Mary falls in love with him. Neither is really explained. They both just kind of happen.

Plan the perfect wedding: History is filled with terrible wedding toasts. But Tim is able to tweak his and Mary's big day until he settles on the best possible best man speech.

You can learn from mistakes without going back in time: That said, Curtis wisely stops short of having Tim re-do every tiny blunder. The movie's already over two hours as is.

Life is supposed to have some surprises: Like the fairly major "catch" that Tim's dad withheld from him during their initial chat, seemingly solely to give the movie a third act twist.

The moral of the story needs to be clear: Unlike Tim, audiences aren't necessarily going to go back to see what they missed. So Curtis makes sure the movie's big feel-good message is extremely obvious, having Tim explicitly narrate it while "About Time" wraps up.

Even time travel has its limits: Not all the movie's rules and internal logic makes sense (especially not the aforementioned late-movie curveball), but "About Time" is still charming enough that audiences should be willing to put down their straw diagrams and give Curtis and his cast the benefit of the doubt.

"About Time" opens on November 1.

About Time - Trailer No.1