Movie Review: Two ideas compete for the soul of ‘My Old Ass’ but sweetness finally wins

They say tripping on psychedelic mushrooms triggers hallucinations, anxiety, paranoia and nervousness. In the case of Elliott, an 18-year-old restless Canadian, they prompt a visitor.

“Dude, I’m you,” says the guest, as she nonchalantly burns a ’smores on a campfire next to a very high and stunned Elliott. “Well, I’m a 39-year-old you. What’s up?”

What’s up, indeed: Director-writer Megan Park has crafted a wistful coming-of-age tale using this comedic device for “My Old Ass” and the results are uneven even though she nails the landing.

After the older Elliott proves who she is — they share a particular scar, childhood memories and a smaller left boob — the time-travel advice begins: Be nice to your brothers and mom, and stay away from a guy named Chad.

“Can we hug?” asks the older Elliott. They do. “This is so weird,” says the younger Elliott, who then makes things even weirder when she asks for a kiss — to know what it’s like kissing yourself. The older Elliott soon puts her number into the younger’s phone under the name “My Old Ass.” Then they keep in touch, long after the effects of the ’shrooms have gone.

Part of the movie’s problem that can’t be ignored is that the two Elliotts look nothing alike. Maisy Stella plays the coltish young version and a wry Aubrey Plaza the older. Both turn in fine performances but the visuals are slowly grating.

The arrival of the older Elliott coincides with her younger self counting down the days until she can flee from her small town of 300 in the Muskoka Lakes region to college in Toronto, where “my life is about to start.” She’s sick of life on a cranberry farm.

Park’s scenes and dialogue are unrushed and honest as Elliott takes her older self’s advice and tries to repair relationships with her golf-loving older brother and gloriously odd younger one, who has an obsession with Saoirse Ronan. This is a filmmaker who knows siblings and how they vibe.

Then Chad pops up.

Chad is sweet and thoughtful and goofy and cute and smart and resourceful and really, really into Elliott. “Everything about him feels so right,” the younger wails. A central question in the movie is why My Old Ass wants young Elliott to stay away from Chad, played so beautifully by Percy Hynes White that you want to shake sense into both women.

Both parts of Park’s movie — the coming-of-age tale and the me-visiting-from-the-future tale — work, but maybe not in the same movie, a little like the two different Elliotts. The tone of each part are different, one wistful, the other zany, and together threaten to pull “My Old Ass” apart.

Aside from a stunningly funny ’shroom-induced dream sequence that includes a Justin Bieber concert, Park is strongest exploring the liminal space between one thing ending and another beginning — soft beautiful memories that are sad and yet necessary.

Both Chad and Elliott’s mother (a strong Maria Dizzia) have lovely dialogue about the profound effects that tiny moments of change can have: Sometimes you know it has ended forever — like a baby transitioning from your bed to a crib — and sometimes you never get to say goodbye, like the last day you spent all day messing around with your friends on bikes.

Even if the road is a little rocky, stay for a satisfying end, one in which, somewhat predictably, the younger Elliott offers some wise advice to the older. There’s a moment or two when Chad threatens to overpower “My Old Ass” and steer it into a third movie, but Park knows her way out. It’s a story that has always been about the younger Elliott and seeing her finally steer her boat — literally and metaphorically — is a joy.

“My Old Ass,” an Amazon MGM Studios release that opens in movie theaters in New York and Los Angeles on Friday and wide Sept. 27, is rated R for “for language throughout, drug use and sexual material.” Running time: 89 minutes. two and a half stars out of four.