Solimar is a fifteen-year-old princess in the mountainous kingdom of San Gregorio. Rejecting traditional royal expectations, she prefers hiking boots to fancy heels and wishes she had a voice in governing her homeland. When she visits the sacred forest, monarch butterflies magically embed themselves in her red rebozo, granting her a temporary gift of prophecy but burdening her with the responsibility of protecting the weakened creatures. She sets out on a dangerous river journey to save her kingdom when it falls under attack.

Berto is an ingenious older boy who lives in a multi-level treehouse along the Río Diablo. Working to realize his late father's dream of channeling river water to his parched agricultural homeland in Valle Granada, he considers himself a self-proclaimed flume-ologist. He invents practical devices out of scavenged materials and becomes an essential guide for Solimar's perilous journey down the rapids.

Prince Campeón is the tall, bookish heir to the throne of San Gregorio. Unlike his sister, he lacks ambition for royal leadership and feels trapped by his hereditary position. He secretly plans to abandon his royal duties to travel the world aboard a ship called La Quinta, a desire that complicates his family's expectations.

King Aveno is the greedy, red-faced ruler of a neighboring kingdom. Driven by a desire for personal wealth, he clears the forests on his own land and aggressively seeks to purchase and strip San Gregorio's sacred oyamel fir forest. He views neighboring kingdoms as weak and relies on intimidation, blackmail, and bribery to expand his power.

Doña Ana Socorro is Solimar's silver-haired grandmother and an experienced herbolaria who creates medicines from local plants. Though she adheres to traditional expectations regarding royal appearances, she harbors her own secrets, including the quiet practice of minor enchantments. She acts as a protective guide to Solimar as the young princess navigates her newfound magical abilities.

Doña Flor Espinoza is a powerful curandera, or healer, who lives on the outskirts of the kingdom. While some villagers spread rumors that she is a fearsome witch, she uses her extensive knowledge of magic and herbalism for good. She mentors Abuela and helps Solimar understand the rules and responsibilities of the enchanted butterfly rebozo.

King Sebastián is the rumpled, gray-haired ruler of San Gregorio who prefers working in the streets and fields over sitting in his castle. He deeply values the traditions of his kingdom and organizes a caravan to sell village crafts in Puerto Rivera. He is determined to protect the monarch butterflies' habitat from neighboring threats but remains steadfast in traditional laws regarding royal succession.

Queen Rosalinda is the elegant, dark-haired mother of Solimar and Campeón. She represents the traditional expectations of royalty in San Gregorio and busily prepares for Solimar's elaborate transition into official princess-hood.

Lázaro is a magnificent resplendent quetzal with multi-colored iridescent plumage and a nearly three-foot-long blue-green tail. He serves as Solimar's devoted companion, sharing an unusual communicative bond with the princess and alerting her to danger during her travels.

Zarita is a sentient, talking rag doll created by Doña Flor Espinoza. She slips into Solimar's pocket to accompany the princess on her journey, providing constant encouragement, practical advice, and the unique ability to converse with both humans and animals.

Señor Verde is the thin, mustached, long-time counselor to King Sebastián. He assists the king with the administrative duties of running San Gregorio and is left in charge of the kingdom's affairs when the monarch travels to Puerto Rivera.

Juan Pedro serves as a new assistant to Señor Verde. He secretly operates as a spy, providing inside information to neighboring rivals in exchange for lucrative payouts.

María is Solimar's childhood friend in the village. She is one of the first people to discover the magical print on Solimar's rebozo and helps test the limits of the princess's newfound prophetic abilities.

Señora Batista is the talented royal chef in the castle of San Gregorio. She prepares meals for the royal family and works closely with Abuela during the castle's occupation to serve enchanted pastries to the guards.

Josefina is Solimar's former tutor. She resides in the village and worries about her romantic prospects until Solimar accurately predicts a marriage proposal from her partner.

Arturo is a loyal subject of San Gregorio and the romantic partner of Josefina. He proves his bravery by aiding the royal family, acting as a decoy to distract rival guards.

Magdalena is Berto's supportive mother who lives in the Valle Granada. She maintained unwavering faith in her late husband's ambitious water retention projects, inspiring Berto to name his river raft in her honor.

Ricardo is a local tortilla-maker in the village of San Gregorio. He relies on the success of the kingdom's artisans and frequently checks on the weather to ensure the safe passage of the trade caravan.