Arteiro emerges as the solitary chick of Toto and Lala in an Adélie penguin colony in Antarctica. His early life reveals persistent curiosity and adventurousness, driving him to explore beyond colony boundaries despite parental cautions. This behavior sparks incidents like attempting friendship with a skua chick, resulting in injury and unconsciousness after an attack.

As an only chick, he forges a strong bond with Pepe, another sole offspring distinguished by pink plumage. They undertake explorations forbidden by colony elders. During one venture, Arteiro meets Don, a husky puppy belonging to Antarctic researchers. Through Don, Arteiro learns to distinguish benevolent scientists from threatening poachers, countering the colony's generalized human distrust instilled by elder Pigo.

Maturing Arteiro's inquisitiveness heightens peril. He and Pepe strand on drifting sea ice after mimicking skua flight attempts, facing leopard seal predators. Subsequent capture by poachers forces Arteiro into resourceful leadership. Confined aboard the poachers' vessel with Pepe and a Macaroni penguin named Mak, he engineers escape using a stick to manipulate the cage latch. The flight includes evasion aided by Jack, a Saint Bernard dog who distracts poachers with false storm warnings.

Their colony return coincides with a poacher raid targeting chicks. Arteiro joins the pursuit, witnessing fatal confrontations and retaliatory natural events that claim colony members, including his father Toto. This loss triggers pivotal development, compelling Arteiro to accept leadership duties under Pigo's designation. His command emerges during seasonal migration to the North Sea, where he invites Mak to join their colony despite species differences.

Arteiro's journey transforms him from a recklessly curious hatchling into a protective figure. Human threats, survival trials, and paternal loss forge his shift toward communal responsibility, culminating in leadership acceptance for the colony's future.