Fred is an English boy sent to live with a cousin in Brazil after a bout of pneumonia rendered his father unable to care for him. He possesses a deep fascination with stories of Amazonian explorers, using them to escape the reality of his illness. At school he is known as a sensible boy, but the crash awakens a deep-seated desire to take risks and prove himself brave. He is resourceful and quick to act, willing to test unknown waters and try strange foods to keep the group alive.

Con is a prickly, highly guarded English girl who lives with her great-aunt and is regularly sent away to convent schools. She uses sarcasm and hostility as a defense mechanism to cope with her fear and her underlying feelings of abandonment. She initially opposes the group's survival ideas, preferring to wait by the crashed plane and insisting she has no desire to make friends.

Lila is a logical, observant girl traveling to see her grandmother when the plane goes down. She possesses a wealth of knowledge about biology and the Amazon due to her scientist parents. She assumes a maternal role within the stranded group, remaining deeply focused on keeping her younger brother safe while formulating practical survival strategies.

The Explorer is a rugged, deeply scarred man living in isolation among ancient ruins in the Amazon. He dresses in animal skins and wears caiman teeth for buttons. He is highly suspicious of outsiders and fiercely protective of his jungle home, possessing extensive knowledge of survival techniques and the surrounding environment.

Max is Lila's five-year-old brother and the youngest passenger on the ill-fated flight. He acts unpredictably, alternating between panicking and making observant discoveries in the jungle. His young age makes him highly vulnerable, requiring the older children to constantly monitor him and physically assist him during their journey.

Abacaxi is a baby sloth discovered by Max early in the children's survival journey. Orphaned and vulnerable, the creature requires constant attention and quickly bonds with the group.

The Pilot is an elderly man tasked with transporting four children to Brazil. He suffers a sudden medical emergency mid-flight, forcing the plane into a catastrophic crash landing in the rainforest.