Reina is a New York-based copy editor at Stellar Publications. She harbors a deep emotional attachment to the memory of her late father, who died in a plane crash when she was eight years old. When an opportunity arises to take over a walking assignment on the Camino de Santiago, she impulsively volunteers, packing her father's 1997 trail journal and wearing poorly suited Doc Martens.

Isabelle is a 17-year-old student attending a boarding school in Pau, France, far from her home village of Dur in Andorra. When a deadly family feud over mountain development rights puts her life in immediate danger, she decides to vanish into the wilderness to protect her siblings. Adopting the pseudonym Joan, she begins walking the Camino de Santiago with failing sneakers and no money.

Peter is an American traveler walking the Camino de Santiago in 1997 with his brother. He documents his journey meticulously in a black journal and takes extensive photographs of his fellow pilgrims. Quiet and observant, he carries a first-aid kit and quickly notices the physical struggles of those around him.

Matt is the lead writer for Journey magazine and Reina's primary workplace rival. He possesses an arrogant demeanor and frequently belittles his colleagues, specifically targeting Reina with the condescending nickname Velma. After a mugging delays his trip to Spain, he finds himself competing directly against her for the feature story.

Ruben is an ambitious Andorran cattleman and the patriarch of the Vidal family. He functions as a self-declared authority in the remote village of Dur, aggressively pushing for the development of a ski resort on communal mountain land. His stubborn pride initiates a violent conflict that endangers his children.

Senor Sansas is the calculating patriarch of a rival family in Dur. Following the deaths of his teenage twin sons in a car crash, he demands absolute revenge against the Vidal family. He views Isabelle's deciding communal vote as a threat and actively hunts her across the border.

David is Peter's younger brother who accompanied him on the 1997 pilgrimage across Spain. Outgoing and sociable, he serves as an energetic counterpart to his quieter sibling. He survived the catastrophic plane accident that killed Peter but vanished from the hospital shortly afterward on crutches, leaving his family without answers.

Ted is a sophisticated Canadian hiker walking the trail with his brother. He serves as a morale booster for the people he meets, offering practical medical help for trail injuries and constant encouragement. His cheerful optimism provides critical support for struggling walkers.

Ned is a good-natured Canadian man undertaking the physical challenge of the Camino on the advice of his doctor. Despite struggling significantly with the steep mountain ascents and his own physical limitations, he maintains a steady determination and a warm sense of humor.

Xavier is Isabelle's 16-year-old brother. He takes the back mountain route from Andorra to France to warn his sister about the impending arrival of the Sansas family, risking his own physical safety to ensure she has time to escape.

Ana is Isabelle's younger sister back in the village of Dur. She is removed from the immediate physical danger of the mountain feud and sent to live with an aunt in Barcelona for her own safety.

Gemma is the child of a French minister and Isabelle's closest friend at the boarding school in Pau. She willingly volunteers for agricultural chores just to spend time with her friend and immediately agrees to lie to the school authorities to cover Isabelle's sudden disappearance.

Brenda is the managing editor at Stellar Publications. She controls the writing assignments for the upcoming Spain issue and ultimately approves Reina's last-minute request to replace Matt on the Camino trip.

John is Reina's dependable boyfriend in New York. He represents the stable, predictable life she leads before leaving for Spain, though she frequently forgets to contact him once the physical demands of the trail take over her daily routine.

Aunt Robbie is Reina's aunt who assists her in getting ready for the sudden departure. She held the family together following the devastating plane crash that killed her brother-in-law and the subsequent disappearance of Uncle David.

Karen was Reina's kind mentor at the magazine. She suffered from failing health before her death, and Reina harbors deep resentment toward Matt for allegedly stealing a major story from her during that vulnerable period.

Jen is an American traveler who meets Isabelle on the very first day of the trek. She becomes part of the core walking group, frequently sharing historical legends about the route and providing companionship during the long stretches across northern Spain.

Joe is an American pilgrim walking alongside Jen and Isabelle. He participates in the daily routines of hostel life and contributes to the group's collective historical knowledge of the various Spanish villages they pass through.