Audiences will flock to theaters this weekend to see 'Edge of Tomorrow,' the latest sci-fi action flick featuring Tom Cruise in his natural environment: running from things, shouting, touting some guns, and fighting off a serious alien threat. But what viewers will be wonderfully surprised to discover is that Cruise isn't the real action star of his own film. Instead, it's Emily Blunt, best known for previous supporting roles in 'The Devil Wears Prada' and 'Looper,' and someone you'd least suspect.

Although the very smart marketing would have you believe that this is yet another vehicle for Tom Cruise to do what Tom Cruise does best, 'Edge of Tomorrow' reveals its clever trickery early on, as the actor's Major Cage is little more than a handsome, smiling military publicity representative, woefully ill-suited for combat. After a bit of table-setting in which Cage ticks off a superior and sent off to war with the big bad aliens, he meets the true badass of this story: Rita Vrataski, dubbed by many as "The Full Metal Bitch" -- a sexist moniker readily dismissed by the film when an admirer and fellow soldier makes the unfortunate mistake of addressing Rita as such to her face, earning him a righteous gut-punch. It's such a simplistic and fleeting moment, but one that beautifully addresses casual sexism and the triviality of intent.

This is our introduction to Rita, a sword-wielding, heavy metal fighter who managed to kill over 100 aliens on her first day. She is better and tougher than her male counterparts, who all know to stay out of her training space. Rita is also the only one who can help and train Cage, who has been covered in the blood of an alien Mimic, granting him the ability to relive the same day of battle over and over again -- which also might be the key to helping the humans win the war. Such an advantage might be wasted on an unseasoned soldier such as Cage, but with the help of Rita, Cage can only get better. What makes Rita particularly integral to the plot beyond her impressive abilities in combat is that she once also had the same ability to relive the day over and over again. Without Rita, Cage would be utterly lost, making him wholly dependent on the knowledge and skills of a woman to help him learn how best to utilize this new ability in order to save humanity.

Unlike the majority of action films, we finally have one in which the woman is the badass warrior, and the man is, for all intents and purposes, her sidekick. Sure, by film's end, Cruise does what Cruise is going to do and ultimately executes the action that saves the day, but it takes Rita to get him to the very end and teach him the most important lesson of all -- one that can't be taught in combat training, but must be learned through the harrowing experience of war: the value of sacrifice. Over and over again, as many days as Cage is given to live, we watch as Rita marches off to her own death, willing to sacrifice her life if it means saving the world, while Cage does everything in his power to secure an outcome in which they both survive. This difference is what makes Rita a superior warrior and a superior hero: a real hero knows that the needs of the many outweigh the needs of the few, and that their own, singular life is insignificant in comparison to the entire human race.

Blunt's Rita calls to mind the tough, practical nature of Sigourney Weaver's Ripley, particularly in the 'Alien' sequels, after she's already been through the proverbial trenches with these relentless creatures and knows what has to be done, the sacrifices and hard choices that must be made. It's rare that we get a bonafide female action hero in a legitimately good film with a legitimately good role -- you almost want to thank Tom Cruise for being a good sport and letting Emily Blunt make him look like such a weenie in comparison.

More From ScreenCrush