Lupita is a 13-year-old Mexican girl defined by her relentless optimism, which earns her the nickname "Mañana." After her father is swept off a fishing boat, she sews a money pouch into her clothes, dresses as a boy, and walks to the United States to find work. She is deeply loyal to her family and heavily reliant on her faith to sustain her through harsh desert crossings and grueling agricultural labor. Her sharp observations help her survive in a completely foreign environment.

Salvador is Lupita's 15-year-old brother who acts as her guide during their trek to California. He resents his poverty and the menial nature of the jobs available to him in Mexico, preferring to dream of wealth and flashy cars. Burdened by his culture's expectations of masculinity, his protective instincts clash with a growing desire to embrace Americanized independence.

Carmela is the hardworking, illiterate mother of Lupita, Salvador, and four younger children. Facing the immediate loss of her home to a local money lender, she makes the agonizing choice to send her two eldest teenagers across the border to work. She anchors her children with a strong sense of duty.

Consuelo is Carmela's sister who moved to the United States twenty years prior. Worn down by poverty, a difficult marriage, and relentless agricultural labor, she initially views her relatives as an unwelcome burden. She secures them jobs picking summer squash and zucchini, demanding a portion of their wages for room and board before slowly warming up to her niece.

Lucio is the well-dressed, confident teenage grandson of Fidencio who insists everyone call him "Lucky." As a mechanic and American citizen of Mexican descent, he openly rejects his Mexican heritage in favor of gringo culture. He mocks traditional customs and encourages Salvador to spend his money on flashy clothes rather than sending it home.

Irela is the sharp eight-year-old daughter of Consuelo and Hermilio. Precocious and observant, she quickly warms to Lupita upon learning her older cousin once dreamed of becoming a teacher. She is eager to share her knowledge of English with her newly arrived relative.

Hernando is the father of the Torres family. His tragic accident on Captain Ortega's commercial fishing boat plunges his wife and six children into immediate financial peril. The memory of his warmth and hard work heavily influences Lupita's actions throughout her journey.

Captain Ortega is a wealthy man in Ensenada who owns the fishing boat La Estrella. He holds a low opinion of Salvador, dismissing him aggressively when the teenager asks for a job following Hernando's accident.

Dorotea is Captain Ortega's daughter. She engages in an unapproved, secretive romance with Salvador, gifting him an inscribed pocketknife that later becomes an important bartering tool for his survival during the border crossing.

Hector is an American citizen of Hispanic descent who works for the railroad. He discovers Salvador and Lupita hiding in a train hopper. Rather than reporting them to immigration authorities, he drives them to Colton, California, and secures them jobs in exchange for a perpetual cut of their wages.

Hermilio is Consuelo's husband. Sidelined by lung and back problems, he spends his days collecting welfare assistance and his nights drinking and playing cards at the local cantina. He is sullen and initially tries to force Salvador and Lupita out of his home.

Fidencio is Hermilio's brother. He drives a worn pickup truck that ferries his extended family and other migrant workers to the agricultural fields across the Coachella Valley each morning.