A powerful earthquake strikes, throwing Maya from Seltzer. The panicked horse breaks his reins and bolts. A massive landslide across the river creates a violent wind blast that lifts Maya off the ground and slams her down. She finds Artemisia trapped beneath fallen logs as the dammed river rises rapidly. Maya frantically pulls the timber off, freeing the horse just before a surge reaches them.

A strong aftershock triggers another rockslide that buries Klee’s body. The tremor sends Maya tumbling downhill into a rock face. She suffers severe injuries: a painful right foot, a gashed right arm, and a head injury that leaves her disoriented with blurred vision. Maya loses consciousness.

Later, Artemisia’s persistent nudging awakens her near sunset, with the river lapping at her boots. In agony, Maya crawls to a tree and pulls herself up. The wind blast has stripped every leaf from the aspens. She hops to a depression between the trees, makes a mattress from fallen leaves, and tries unsuccessfully to remove her boot. As darkness falls, Artemisia is no longer in sight. Maya calls for her but receives no response. She pulls the small toy horse from her vest pocket for comfort before collapsing.

At dawn, Maya finds Artemisia still nearby. Her ankle throbs and her arm wound oozes. She worries about her family’s safety and wonders whether they think she is dead. After making a cane, she reaches the river to drink and soak her foot. She removes her boot, revealing a grotesquely swollen, broken ankle. Maya talks to Artemisia, hoping to gain the mare’s trust.

While it is still light, Maya eats one of the apples and leaves grain for the horse. Staring at the vast night sky, she feels small and wonders if anyone will find her. The next morning, the grain is gone and Artemisia browses closer. Maya discovers two trout trapped in a river pool. Desperate with hunger, she spends an hour trying to start a fire by focusing sunlight through a binocular lens, creating smoke but no flames. Frustrated, she gives up and eats her last two apples.

That evening, Artemisia eats grain while Maya speaks softly to her and sings a version of “Twinkle, Twinkle, Little Star,” using her mother’s name, Ellie.

On the third morning, swarms of newly hatched mosquitoes besiege Maya. She watches Artemisia rolling in water and dirt for protection and copies her, covering her exposed skin with mud for relief. Weak with hunger, Maya eats some of the molasses horse feed and finds it tolerable. That night, nightmares torment her; she dreams of Grandmother washing her mouth with soap, then of being hunted by a mountain lion. She also dreams that her parents are swimming desperately but cannot reach her.

On the fourth morning, Maya’s worsening leg pain forces her to scoot to the river. Artemisia wanders over a ridge and disappears, causing Maya to weep in despair.

Hours later, when the horse returns, Maya proudly tells Artemisia that she has finally succeeded in making a fire with the binocular lens and cooks one of the trout. She speaks to the horse about her parents, saying she is proud that they never gave up on their dreams. After eating, she puts grain near the fire. Artemisia comes close enough for Maya to touch her, but Maya deliberately holds back to avoid spooking the mare.

Maya loses track of time but estimates that she has been stranded for approximately a week. Her arm wound has become infected; it is red, hot, and stiff, and she has developed a fever. In the middle of a dark night, violent sounds wake her, and she realizes that a mountain lion is fighting with Artemisia. The violent struggle ends abruptly in silence.

When moonlight breaks through clouds, Maya sees a ghostly white apparition moving toward her—it is Artemisia, unharmed. Maya realizes that the mountain lion was hunting them and that they must leave. For the first time, Artemisia nuzzles Maya without pulling away, and Maya strokes her head and neck. The horse stays vigilant beside Maya through the night.

The next morning, Maya sees yellow pus oozing from her infected wound. Knowing that she must escape, she fashions a makeshift Comanche Coil by tying drawstrings and a binocular strap to her rolled jacket. She secures it over Artemisia’s shoulders. Using a log for leverage, Maya painfully mounts the horse bareback and tucks her knees under the coil for support, easing the pain in her broken ankle. Artemisia walks forward, carrying Maya away from the grove.

Feverish and in pain, Maya rides through the flood-damaged landscape. The wild stallion Remington appears on a ridge and calls to Artemisia, who answers. They attempt to cross the swollen river, but Maya slides off into the water mid-crossing. She clings to the Comanche Coil as Artemisia drags her through the current, then manages to pull herself back onto the horse. When they are caught in a rainstorm, they become disoriented. After the storm clears, they find the familiar gorge and begin the difficult climb toward camp.

Reaching the top, Maya is filled with anticipation but finds that the campsite is severely damaged by the flood. The tepees and the office tent are gone, the kitchen tent is empty, and one corral is disassembled. She rides into the one remaining empty corral and collapses in despair, believing that her family may be dead. In a feverish state, she hears guitar music and horse bells in the distance. Realizing that her family must have relocated to the old campsite nearby, Maya secures Artemisia in the corral and hobbles toward the sounds, using a crossbar as a crutch.

She sees her family around a campfire. Overcome with emotion, she waits in the dusk until Golly, the dog, spots her. The family rushes to her; Payton comes first, then Aunt Vi, then Uncle Fig with a towel. Finally, her grandfather, Moose, pushes forward to reach her and scoops her into his arms. Sobbing emotionally, Maya wraps her arms around his neck and calls him “Grandpa” for the first time.

After Maya goes to the hospital for stitches and a cast, Moose carries her to her bed at the ranch. Surrounded by family, including Golly jumping onto the bed, Maya recounts her ordeal. The family explains their experiences: Aunt Vi and Payton had gone to the dentist and then to the ranch, where they were during the earthquake, while Moose and Uncle Fig were at a store in town. Returning to the flooded camp and finding Maya missing, they launched a large-scale search-and-rescue operation after Seltzer returned alone.

Aunt Vi announces that she is returning to camp, which a ranch hand is currently watching; she invites Maya to join her once her cast is removed. Vi reveals that Payton had argued against returning to camp, wanting to stay at the ranch with Maya instead. Before leaving, Payton gives Maya a leather drawstring bag that he made for her toy horses, as their box was ruined in the flood. He explains the brown-and-white horse is the only one missing. Maya shows him she has kept it in her vest pocket the entire time. She explains that she had left camp trying to find an eagle feather for him as a thank-you gift but found Artemisia instead. Payton tells her about a planned pack trip at the end of August and makes her promise to heal quickly so they can go together.

Artemisia paces her corral enclosure, where food and water are provided regularly. A woman handler works with her every few days, lunging her and giving cues, and Artemisia responds as she remembers from past training. The woman grooms her, removing burrs and knots from her mane and tail. After several weeks, the woman blankets, saddles, and rides Artemisia on a dirt track and nearby trails.

While the routine becomes familiar, Artemisia does not feel that she belongs with the other domestic horses. Every evening at sunset, the wild stallion Remington appears on a nearby ridge and calls to her. Artemisia answers his calls. She grows accustomed to his visits, pacing restlessly each afternoon in anticipation and only calming when he appears.

With her cast removed, Maya returns to the Sweetwater camp with Moose and Uncle Fig. Aunt Vi greets her, leading a healthy and groomed Artemisia, and tells Maya that Artemisia is hers now. Maya has a joyful reunion with both Aunt Vi and the horse. She settles back into camp life.

A few days later, Maya and Aunt Vi ride out, retracing Maya’s path to the aspen grove. Remington shadows them throughout the journey. Aunt Vi tells Maya she considered freeing Artemisia but chose not to make that decision alone. Riding across a vast plain at sunset, Aunt Vi encourages Maya to let Artemisia run. Maya gives the horse her head, and they gallop freely. The experience fills Maya with profound joy and connection.

As they return to camp, Remington waits on the ridge. Reflecting on the value of freedom over confinement, Maya dismounts and removes Artemisia’s saddle and bridle. Looking into the horse’s eye, she sees the spirited, wild mare that her mother once knew. Maya slaps Artemisia’s thigh and tearfully tells her to run. Artemisia hesitates, then bolts up the hill. Remington trots to meet her, their muzzles touching briefly. Artemisia determines their path, and he follows. Maya watches the two horses run across the ridge together, their white coats illuminated against the darkness like ghostly spirits “painting” the wind. Through her tears, Maya promises that they will meet again.