The assured coming-of-age film “Turtles All the Way Down,” based on John Green’s blockbuster young-adult novel of the same name, takes its title from an apocryphal story: An older woman at a science lecture posits that the Earth rests on the shell of a tortoise, which in turn sits on the back of a larger tortoise, and so on, to infinity.
A never-ending stack of reptiles is an evocative image and an expressive paradox. It’s especially fitting for “Turtles,” a movie based on a book propped up by an ever-expanding young-adult canon that traffics in the romance of pain and the pain of romance. (Which came first in that sequence of romance and pain? It’s turtles all the way down.)
Directed by Hannah Marks (“Don’t Make Me Go”), the movie centers on Aza (Isabela Merced), a teenager with obsessive-compulsive disorder whose contamination anxieties are impeding her ability to build intimacy with others. These struggles grow urgent once Aza reconnects with Davis (Felix Mallard), a childhood friend who wants to be more than that. She likes him back, but panics at the thought of kissing him; brushing lips would mean swapping bacteria.
Aza squirms through this dilemma in sessions with her therapist (Poorna Jagannathan) and on hangouts with her gregarious best friend, Daisy (Cree, a scene stealer). But other than Aza’s daily dose of anxiety, which often prompts her to prick at her finger until it bleeds, much of the movie wants for conflict. When the story begins, Davis’s ultrarich father has gone missing, but even that great mystery is less a source of forward momentum than an excuse for our teenage lovebirds to frolic without supervision.
The movie’s ambling, novelistic rhythms might have passed muster had the movie filled its empty spaces with strongly delineated characters. As is, only Aza emerges fully formed; the handsome Davis is more statuette than human, and Daisy mostly suffers a bad case of Sidekick syndrome: pluck without complexity. A hasty third act tries to frame the movie as a friendship love story, redirecting attention from the trials of smooching to the value of mutual support. But the efforts feel like too little, too late.
What “Turtles” does offer in surplus is texture, thanks to Marks’s springy, stylish direction. Any time Aza confronts a thought spiral about germs, Marks pairs voice-over of Aza’s frantic inner monologue with images of neon-colored microbes writhing in a petri dish. These moments are intrusive and unsettling, and together form one of the more dynamically authentic on-screen depictions of O.C.D. that I’ve seen.
Like many adolescent stories of this subgenre, the movie’s central question hangs on identity and its enigmas. Among Aza’s deepest worries — and this brings us back to the turtles — is that her personhood is like a Russian doll: a series of empty casings with nothing at the core. What makes Aza Aza? Is O.C.D. an essential part of who she is, or is it holding her back from her true self? “Turtles,” to its credit, never locates a specious source of Aza’s troubles, nor does it try to unveil a solution to her suffering.
Turtles All the Way Down
Rated PG-13 for debilitating anxiety and other adolescent woes. Running time: 1 hour 51 minutes. Watch on Max.