Not that you would know it from the young Irish actor's last big role, the somber, bushy-bearded landowner Levin in last year's "Anna Karenina." Here, though, he is slightly more grounded than Grant (and his copper hair color provides fodder for ginger jokes, an Anglo staple) as Tim, a lawyer-to-be who is gobsmacked to learn at age 21 that the men in his wealthy family of eccentrics share the ability to go back in time. That the news is delivered in the most charming off-handedly fashion by his father in the form of Nighy, who never fails to amuse at the very least and astonishes almost always whenever he is onscreen, undercuts the questions that nitpickers might have about the process.
One major caveat: You can only revisit and revise portions of your own life. Or as Nighy puts it, "You can't kill Hitler or shag Helen of Troy." That Tim tends to go into a Narnia-esque wardrobe to begin his detours into the past adds a quaintly homey touch that is light years away from Star Trek or even H.G. Wells.