In the suburban town of Hatfield, Pennsylvania in the late 1990s, Caitlin’s teacher Mrs. Miller gives her class an assignment to pick a foreign country and write letter to a pen pal there. Though Caitlin knows almost nothing about Zimbabwe, she chooses it anyway because something about the mystery intrigues her. She does some research before sending off a letter.
Meanwhile, in Zimbabwe, Martin is at the top of his class. His family lives in a poor region outside the of Mutare, the third-largest city in the country. Not every student at his school gets a pen pal, but because Martin is one of the best students in his class, he receives Caitlin’s letter and is tasked with writing one back. He is fascinated with imagining Caitlin’s life, since he doesn’t know much about the U.S.
Even after the school assignment ends, Caitlin and Martin decide to keep writing back and forth to each other. This proves to be particularly difficult for Martin, since Zimbabwe is in economic turmoil, and stamps are getting increasingly expensive. Things get even more difficult when Caitlin asks Martin for a photograph (since photos are rare and expensive in Zimbabwe at the time), but Martin always does what he can to try to please Caitlin, eventually finding a photo to send.
Though at first Caitlin and Martin are guarded in their letters, eventually, they feel more comfortable talking about the real circumstances of their lives. Martin sends Caitlin a photo that reveals how small of a house his whole family lives in. Meanwhile, Caitlin’s family can afford to buy her a car before she even gets her driver’s license. Caitlin gets the idea that she should send some of her babysitting money to Martin to see what happens.
At first Caitlin sends the money in secret, and Martin is shocked but grateful to receive it, since the conversion rate means it’s enough for Martin and his family to buy several weeks of food. When Martin’s father loses his job due to turnover at the paper mill where he works, Martin’s financial situation suddenly becomes even worse, and he risks getting kicked out of school since he can’t pay tuition. Caitlin decides to send money to help pay for Martin’s education. His family buys chicken to celebrate, which they usually only eat for Christmas.
When people in Caitlin’s life find out about the money that she’s sent to Martin, some worry that he’s a scammer. Caitlin’s mom, however, decides to put together a care package of clothes and other necessities for Martin’s family. Among those gifts are shoes for Martin’s mother—she grew up in poverty without shoes, and the new shoes help her be recognized as a member of society.
As Martin continues to do well in school, he is offered the opportunity to study at one of the most elite boarding schools in Zimbabwe. This could put him on track to become a doctor or a lawyer, with the possibility of even going to university in the United States. The tuition is much more than Martin’s family can afford. But with some help from Caitlin (as well as some help from Martin’s well-educated cousin Sekai and her husband, Alois), Martin manages to scrape together enough money to attend the new school, getting his deposit in just before the deadline.
At his new school, Martin begins formulating a plan to go to college in the United States. His school friend Wallace, who comes from a rural region of Zimbabwe similar to Martin’s home, gets accepted to an American university, which proves to Martin that his dream is possible. Wallace even ends up staying with Caitlin’s family while he attends school. However, Martin will need a full scholarship to be able to afford college, and few schools are willing to give one to an international student. Martin also scores lower than he needs to on the SATs, which hurts his chances even more.
When it gets to be college acceptance season and none of the colleges that accepted Martin have offered enough money, Caitlin and her mom begin to worry that Martin’s dream won’t come true. Caitlin’s mom makes one last attempt to contact the president of Villanova University (since she got a good feeling from the admission officers there), and at the last moment, he pulls some strings to get Martin a full-ride scholarship.
After years of writing to Caitlin from afar, Martin finally gets on a plane and goes to meet her at the Philadelphia International Airport. There, Caitlin’s mom and Caitlin’s dad greet him as if he’s a member of the family, and he greets them the same way. They drive back to their home, showing him the college he’ll soon attend. Then, the next day, they throw a party for him with friends and family.
Years later, Caitlin and Martin are still friends. Martin is there at Caitlin’s wedding to give a speech. They meet again right before the publication of their book to reminisce. Caitlin is worried about how things might change now that their story is going to be shared with the world, but she is motivated by the hope that young people might read her book and be inspired to do similar acts of kindness.