With beloved films such as Toy Story, Wall-E, Ratatouille and Up, Pixar challenged the idea that cartoons are just for kids by offering awe-striking spectacle, compelling characters and mature storytelling involving themes or rivalry, loneliness, prejudice and grief. Even the Finding Nemo sequel Finding Dory shouldered heavy meaning by turning its forgetful fish into a role model for differently abled viewers.

But the Cars branch of Pixar has more often been regarded as a kiddie-focused affair, what with its simpler designs, unchecked silliness, and unanswered questions about how a world with living cars (but no humans) even works. But with Cars 3, director Brian Fee digs deep to appeal to grown-ups by spinning a parable about aging and mortality.

After years of racking up wins, arrogant Lightning McQueen (Owen Wilson) is rattled once he realizes a new crop of up-and-coming race cars risk making him obsolete. Chief among them is the sleek, speedy, and shade-throwing Jackson Storm (Armie Hammer), who blazes past the iconic red racer and then adds salt to the wound (or sugar to the gas tank) by telling the press, "Lightning McQueen has been a role model of mine for years now. I mean a lot of years!" As Lightning's old pals are pressured to drop out of racing one by one, he pushes himself to the breaking point, literally, causing an alarming car crash that's pretty brutal stuff when you remember he's the hero of a kid's movie.

As the next racing season approaches, the physically healed but ego-hurt Lightning goes on a road trip to get in touch with the racing roots of his late mentor Doc Hudson (the late Paul Newman, thanks to re-used dialogue from the first Cars). But as he looks to his past to inspire his future, he's forced to drag along his new trainer, a plucky yellow car called Cruz Ramirez (Cristela Alonzo), who knows all there is about motivation and the advanced tech training regiment of Jackson Storm and his ilk, but nothing about getting her wheels dirty. Together, this odd couple roars toward the season's career-defining race. Along the way, they'll unveil deep personal secrets, endure wacky adventures, and face off against a volatile, fire-spouting school bus called Miss Fritter (Orange Is The New Black's Lea DeLaria) in one of the series' weirdest action sequences.

Fans of the bucktoothed tow truck Mater (Larry the Cable Guy) might be disappointed that he's little more than a glorified cameo appearance in Cars , while the rest of the Radiator Springs crew is shunted to the sidelines. But props to Fee for making way for a fresh story with some exciting additions. Pompous and caring only about winning, Jackson Storm seems the Eve Harrington to Lightning's Margo Channing or the Nomi Malone to Lightning's Cristal Connors, ready to pounce on his role model at the slightest sign of weakness. At first, I suspected Lightning might take the cocky car under his wing as the curmudgeonly Doc once did for him, in spite of his bad attitude. But rather than a tale of merciless ambition, Cars 3 carves out a surprising route by introducing Cruz as a wannabe racer who has the drive, but lacks confidence. Through mentoring her, Lightning finds a new friend and a new leash on life, and a new way to be a part of the sport he's dedicated his life too.

Ultimately, Cars 3 is a bit all over the road. It zigs from the high-octane action of the speedways, to maudlin moments with schmaltzy speeches, to whimsical slapstick and an abundance of "ha ha you're old" gags at Lightning's expense. With so many of those, that runner gets old quick, especially as things stretch to a nearly two-hour runtime. Thankfully, with each pit stop, the film highlights some charming new characters, each bringing a bit of fun and flavor. My personal favorite was Margo Martindale's old-school racer, who laments she never had a fling with Doc, shrugging, "He didn't like fast women, and I was the fastest around!" This cheeky humor plays well in this weird world of living cars, who don't have hands but somehow operate such delicate technology as iPads and film projectors.

If you're the kind of person that gets caught up on such particulars, Cars 3 will frustrate as it blazes by them, gunning toward earnest emotion and a winsome finale. But I'd advise just give in and enjoy the joyride, bumpy, bonkers and bittersweet as it is.

Cars 3 opens Friday, June 16.