After guerrilla soldiers destroy his village, twelve-year-old Santiago must navigate a perilous sea voyage to the United States to protect his younger sister. Santiago assumes the role of protector for his four-year-old sister, Angelina, as they flee the violence of their home in a small cayuco. The narrative follows their physical struggle against the elements, including shark-infested waters, extreme heat, and violent storms, while they evade military forces. The story is presented as a linear account of their escape, emphasizing the stark contrast between the children's vulnerability and the harsh reality of their environment.

Readers frequently highlight the intensity of the survival elements and the emotional weight of the children's situation. Discussion often centers on the author's ability to present complex geopolitical issues through the perspective of a young protagonist. Critics note that the pacing remains consistent with the urgency of the characters' flight, maintaining tension throughout the voyage. Many readers appreciate the focus on the resilience required to navigate both natural and human-made threats. The book is often cited for its effectiveness in humanizing the experiences of those fleeing conflict zones.