It's the summer before his final year of middle school, and like Greg Heffley (Zachary Gordon), the "Diary of a Wimpy Kid" film series appears to be slowly growing up. The third and, thus far, wisest installment based on Jeff Kinney's best-selling books, "Diary of a Wimpy Kid: Dog Days" is a slim notch ahead of the pleasant 2010 original and a sizable improvement over 2011's unctuous "Diary of a Wimpy Kid: Rodrick Rules"—a film in which Greg's obnoxious, torturous older brother Rodrick (Devon Bostick) decidedly did not rule. This time, returning director David Bowers and screenwriters Gabe Sachs and Maya Forbes & Wallace Wolodarsky (2008's "The Rocker") have shaved off Rodrick's more abrasive side, turning him into less of an insufferable caricature and more like a sibling who, yes, occasionally taunts his little bro, but is also there for him when the going gets tough. Furthermore, Greg's parents, particularly father Frank (Steve Zahn), are given the chance to come into their own after two movies of existing on the periphery. By delving a little deeper, "Dog Days" has become a gently moving slice-of-life in between the slapstick, albeit one that is a bit neutered by a PG rating and targeting a demographic between about 8- to 13-year-olds. Is it heavy on plot or all that hard-hitting? Not really. But for 94 minutes, the movie does its job as a late-summer family entertainment.

School's out for three months and soon-to-be-eighth-grader Greg Heffley has just two goals: to play as many video games as he can, and to figure out school crush Holly Hills' (Peyton List) phone number so he can maybe spend some time with her (signing his yearbook, she was pulled away with still two digits left to scrawl). In an attempt to force Greg to do more with his time than just sit in front of a television screen, his dad takes away his video games and signs the two of them up for a competitive Wilderness Explorer troupe. Things start to look up when Greg accompanies best friend Rowley (Robert Capron) to his family's country club and discovers Holly is also a member. Desperate not to have to accompany his father to work for a non-paying intern program, Greg finds himself lying to his family about getting a job at the club, then scurries there every day to hang out with his friends. It is only a matter of time, however, when his charade is bound to come crashing down. For the first time, Greg will understand why it stung Rowley so badly earlier in the summer when his parents told him they were disappointed in him.

As with its predecessors, "Diary of a Wimpy Kid: Dog Days" doesn't so much follow a strict narrative throughline as it juggles a variety of subplots and misadventures. That's quite all right, though, since Greg is an affable protagonist, one prone to making mistakes and then learning from them. The struggle to form a father-son bond is especially well written and played by Zachary Gordon, as Greg, and Steve Zahn (2009's "A Perfect Getaway"), as father Frank. The two of them don't outwardly share the same interests, but, as they come to find, the love and respect they share for one another is something that comes more naturally when they don't try to push it. A brief falling-out between Greg and Rowley is nicely handled, as well, since they are pals who aren't necessarily mad at each other but feeling individually guilty over their actions (for Greg, it's accidentally sending out a damning email to his mom to everyone on Rowley's father's address directory, and for Rowley, it's having to lie to Greg because his parents don't want them hanging out anymore). Like kids of that age, they make up as quickly and easily as their relationship rashly severed; that's just a part of being in between a kid and a teenager.

Lest it seem as if the movie verges on the too-serious, some of its most fun moments are the lighter ones, from Greg and Rowley riding the terrifying Cranium Shaker at the boardwalk amusement part, to Greg's embarrassment at losing his swimming trunks during a dive meant to impress Holly, to a climactic Sweet 16 party for Holly's stuck-up sister Heather (Melissa Roxburgh) where Rodrick disastrously performs Justin Bieber's "Baby" with his rock band Löded Diper. More acerbic adult humor sneaks in here and there and is certainly welcome, as when Heather reacts negatively to her parents' birthday gift, a necklace that once belonged to her grandmother ("You mean it's used?" Heather says with disgust, snapping the jewelry case shut in their faces). An interlude where Greg accompanies Rowley's family to their summer beach house and ends up playing an uncomfortable game with him and his parents called "I Love You Because..." is also very funny in an out-there way (Rowley to his mom: "I love you because you help me keep my body clean.") Disappointingly, the scene cuts before we learn why Greg loves Rowley's heavily mustached father.

With minimal tweaks, one could see the "Diary of a Wimpy Kid" movies being transferred to a sitcom on Nickelodeon or the Disney Channel. It has a shiny, squeaky-clean small-screen look, and its episodic nature would lend itself well to weekly television. Still, there's something to be said for revisiting these characters once a year as the actors age with their onscreen counterparts. Zachary Gordon is a normal, identifiable lead grounding the material, while Robert Capron (2012's "The Three Stooges") is as winning as ever as virtuous partner-in-crime Rowley. As previously mentioned, Devon Bostick (2009's "Saw VI") is much more palatable now that he's dialed down Rodrick's cruelty, and Peyton List (2011's "Bereavement") is beyond sweet as the object of Greg's affection, Holly Hills. When "Diary of a Wimpy Kid: Dog Days" draws to an end, the viewer's world will not shake, but most audience members will at least be able to say they've had a good time while it lasted. Greg is destined to still make mistakes on his continued journey toward maturity, but this is the first film where one can sense a shift in him that is very much internal. It's not that he's a better person, but he's more aware of right from wrong, of consequences and the value of his friends and family. All of it is a necessary part of growing up.