On her fifteenth birthday, Inés receives a mysterious necklace from her abuela in Mexico. When she wears it, Inés transforms into a monarch butterfly and is given a prophesy to join the migration to save both the butterflies and her family’s legacy. The adventure begins as Inés joins her swarm to navigate the journey to Mexico, which has become increasingly perilous because of humans. Together they travel from New York down to the swamps of Louisiana to the pine-filled mountaintops of the western Sierra Madre, and finally to the Sierra Chincua sanctuary. Along the way, Inés learns about the connection between all creatures, and about the urgent need to protect the monarch’s migration to and from the sanctuary. Once Inés and the monarchs arrive at the sanctuary, she discovers another threat to the butterflies: gangs that clear-cut forests for avocado farms. Yet once reunited with her abuela in Mexico, Inés finally learns why she turned into a monarch, unravelling the family’s mystery and unlocking the secret to saving the monarchs. According to legend, when the Purépecha people were under attack from the Aztecs, the monarchs warned them by turning one of the butterflies into a Purépecha girl who told the people about the imminent invasion. They resisted the attack—in fact, the Purépechas were one of the only tribes to never be conquered by the Aztecs. Forever grateful to the butterflies, the Purépechas started to worship a butterfly goddess and carved large, stone sculptures of her. They also vowed to protect the butterfly forests from all invaders in the future, including the Spaniards who would arrive one hundred years later. The butterfly that became a girl remained in human form, and she passed the magical necklace that Inés now wears to her descendants. Every fourth generation, the daughter receiving it transforms into a monarch butterfly, in order to commune with their monarch ancestors and offer the living swarm assistance, just as the butterflies offered humans assistance on that fateful day 600 years ago. Empowered with this knowledge of her lineage and of her mystical connection to the monarchs, Inés is able to protect this generation of butterflies and simultaneously learn that –whether you are a child or a butterfly—no one is too small to change the world. Divided into four parts to mirror the four life stages of a butterfly—the egg stage, the larva stage, the pupa stage and the butterfly stage—Monarca blends Mexican folklore, environmentalism, and magical realism to inspire readers to protect the sacred world around them.