Amir is a nine-year-old Syrian refugee forced to flee his home in Homs due to the Syrian Civil War. He temporarily settles in Alexandria, Egypt, with his mother and stepfather before sneaking aboard the smuggling ship Calypso. He carries trauma from bombings, which initially damaged his hearing, and seeks comfort in his favorite comic book about two children named Zaytoon and Zaytoona.

Vänna is a 15-year-old Greek girl living on an island heavily reliant on tourism. Her grandparents previously opened the Baldur Inn that failed during the Great Recession, leaving her family in a precarious financial situation. She cleans her yard and misdirects coast guard soldiers to hide Amir in an unused farmhouse.

Colonel Kethros commands a military detachment responsible for capturing undocumented migrants on the island. He views the influx of refugees and foreign tourists as a threat to his homeland's cultural identity. He wears a prosthetic leg due to an injury sustained during foreign military service.

Younis is Amir's uncle who marries Iman after Amir's biological father disappears during the war. He secures a janitorial job at a library in Alexandria but secretly arranges passage to Europe. He pays extra money to secure Amir a spot on the top deck of the smuggling ship.

Mohamed is an Egyptian human trafficker tasked with overseeing the migrants on the Calypso. He enforces order with a pistol and maintains a cynical attitude toward the West. He repeatedly warns the passengers about the discrimination they will face in Europe.

Marianne is Vänna's mother, a bitter woman who holds deep resentments regarding her family's financial struggles and past tragedies. She harbors intense anti-migrant sentiments and takes vigilante action when refugees cross her property.

Nicholas is a young, relatively inexperienced soldier under the command of Colonel Kethros. Unlike his peers, he experiences a crisis of conscience regarding his orders to hunt down undocumented migrants. His hesitation puts him at odds with his commanding officer.

Walid is a Syrian refugee traveling on the Calypso who frequently complains about his fellow passengers. He demonstrates selfish behavior, coveting the belongings of others and expressing open hostility toward Amir over the boy's oversized life jacket.

Kamal is a slim, bald Egyptian man in his late twenties attempting to reach America with a forged green card. He is a former student revolutionary who spent time as a political prisoner in Scorpion Prison following the 2011 Egypt Uprising.

Maher is a Palestinian former English literature student traveling on the Calypso. He burned his fingerprints off with acid to avoid identification. He seeks a quiet place where he can simply read books in peace, separating himself from the political turmoil of his homeland.

Umm Ibrahim is a heavily pregnant woman traveling on the Calypso to secure a safe birth for her child in Europe. She acts as a surrogate mother to Amir during the crossing, sharing her meager food and defending him against hostile passengers.

Teddy is an Eritrean mathematician who fled mandatory military conscription in his home country. Despite having no sailing experience, the smugglers force him to help steer the boat. He shows kindness to Amir by letting the boy briefly steer the vessel.

Iman is Amir's mother. Following the disappearance of Amir's father, she marries Younis to keep the family secure. She constantly worries about her children and practices local dialects while watching soap operas to help the family blend in as they move through Egypt.

Madame El Ward is Vänna's retired French teacher who now coordinates the local migrant detention center. As the daughter of immigrants herself, she uses her language skills and compassion to assist refugees, guiding Vänna on how to smuggle Amir off the island.

Lina is an official with the Ministry of Migration Policy and a childhood friend of Colonel Kethros. She challenges his hyperbolic claims about migrants colonizing the island, providing a more moderate, administrative perspective on the refugee crisis.

Vänna's father struggles with an alcohol addiction and lives in an empty, unhappy marriage with Marianne. He attempts to draw his daughter into his marital disputes by bringing up past family tragedies, but she refuses to take sides.

Harun is the infant son of Iman and Younis Utu, born after the disappearance of Amir's biological father. Amir struggles to feel a connection with his new half-brother as the family moves from Syria to Egypt.