A 1,000 mile trek through sun-scorched deserts and snowy mountains is tough enough without having to deal with unpredictable strangers and undersized boots. It’s all the more strenuous when you’re trying to escape some four odd years of your own mental and emotional meandering.

Cheryl Strayed (Reese Witherspoon), well, strays (she adopts that name after divorce), looking to head to Satisfaction, Purpose, and Meaning via the Pacific Crest Trail. In this adaptation of Strayed’s 2012 memoirs, director Jean-Marc Vallée details in tense, emotional, and often surprisingly comic fashion her journey while frequently visiting her sometimes sordid, always influential past.

That world left behind includes a close and ever-changing relationship with her divorced mother (Laura Dern), a marriage turned to divorce, and demons manifested in drugs and casual sex.

What starts with a vision of a frustrated woman screaming atop a mountain turns into a fascinating biography, a story that can be universally relatable while still deeply intimate. She’s not incapable of this task, one that seems part impetus, just inexperienced, as demonstrated by her hilariously overstuffed backpack and immediate desire to quit. Those moments of lightness blend perfect with moments of sudden terror and terribly heartbreaking flashbacks.

But she’ determined, as is Witherspoon, who commits fully to a taxing and revealing physical and emotional role, carrying a massive pack and a powerful film.

Vallée proves expert at infusing this present with myriad defining life moments, jumping through time and teasing the audience, allowing the viewer to first take in curious sights and sounds before the pieces of the puzzle come together. It’s a compelling structure (and performance) that lands you squarely next to Strayed and on her side, as her frayed past is woven seamlessly into the her present to forge a powerful, unforgettable film.

[star v=45]