Bottom line: If you're looking for pure screen excitement, look no further than The Guardian, a surprisingly effective, heart-stopping action drama that gives us the 411 on what it takes to be a first-rate Coast Guard rescue swimmer. Kevin Costner (showing what made him a movie star in the first place) plays an aging Guard legend who, after a harrowing rescue attempt and the loss of his crew, is reassigned to teach a new group of recruits, including a cocksure young wannabe hero (Ashton Kutcher) who is later revealed to be dealing with the same kinds of demons as Costner's character. Predictably, the two clash in and out of the water, but the tension and emerging respect each demonstrates toward the other is believable and involving. This kind of military swagger has been shown in countless films before, but putting the spotlight on the unique breed that populates the Coast Guard gives the genre renewed life and Kutcher a breakthrough acting opportunity (no, we aren't punking you). Open-water sequences are first rate and expertly done. On the downside, the film is overlong at nearly two and a half hours, a soapy subplot between Costner and his long suffering wife is unnecessary, and the last 20 minutes are a little too mythic. Otherwise, this is a fine, unforgettable motion picture experience that dives right into the heart and soul of a true hero.