Whereas the vast majority of biopic films tend to stray into hero worship territory or dramatic, one-sided documentary-like fare, director Josephine Decker (Madeline's Madeline) takes the long way 'round toward descent into madness in her newest, Shirley, starring Elisabeth Moss.

Like the novel of the same name on which it's based, Decker's Shirley throws its lot someplace between real-life events (Jackson was indeed a writer, was indeed married to writer/educator Stanley Hyman; smoked too much and was probably a little intense before she died at a young 48), but by taking a page from Jackson's own mastery of the unsettling, winds up someplace near murder mystery meets mental health disaster. Or something like it—it's often a challenge to know what's real or not.

We enter Jackson's life through Rosie (Odessa Young), a young woman married to a green PhD candidate (Logan Lerman, who is inconsequential to any of the film's events) who takes the couple to Bennington, Vermont, to work under the tutelage of Jackson's husband. In the midst of a long-running depressive state, Jackson spends much of her time in bed, not writing; sickly and exhausted, she struggles while her husband sleeps around and spills family secrets to potential lovers.

But with Rosie's arrival, inspiration brews, and soon, Jackson is back at her typewriter. Trouble is, the novel, which she bases on a missing young girl from the nearby university, starts consuming her, and that goes double for Rosie who becomes like a ward to the writer…or maybe a lover…or maybe both.

Moss is brilliant as ever, all pent up rage that seeps out at inopportune moments. And the merits of Jackson's works are never called into question, even as she verbally assaults her husband's co-workers and sows discord between Rosie and her beau. She's obviously some kind of genius. Michael Stuhlbarg plays fantastically against Moss as Stanley Hyman; the pair's Who's Afraid of Virginia Woolf? thing cuts deeper and darker, too—they're both horrifying in their own mundane ways, and Rosie, caught between them, starts to question her life and reality.

As do we, particularly thanks to the stellar string-based score from composer Tamar-kali and the jarringly disjointed cinematography from Sturla Brandth Grøvlen (Before the Frost) that phases from average film shots to subtle experimental weirdness so seamlessly we're unsure just when things got so out of hand. Or even if they did. The ending, you see, is up for interpretation, and while it can be a bit of a slog getting there, Moss' performance and the slow burn strangeness help us subsist until we do.

+Moss rules; the music; the cinematography 
-Hard to maintain interest through the slow burn

Directed by Decker
With Moss, Young, Stuhlbarg and Lerman
Hulu, R, 107 min.