It is 1939, and England is poised on the edge of war with Nazi Germany. It is believed that the main target of invasion from the sea will be the south coast, and the biggest threat of mass bombing raids from the sky will be in London. For this reason, children from the inner city are evacuated to the north of England where it is believed the threat from the Germans will be much more slight.
Willie Beech is a scrawny eight-year-old boy from London. For his whole life, he has been physically and emotionally abused by his religious mother, leading him to be extremely timid and fearful. He is evacuated to a small village called Little Weirwold and is placed to live with a man named Tom Oakley, a gruff but kind widower in his 60s. Tom has lost his wife and baby son over 40 years ago and has consequently become somewhat of a hermit, not participating in the usual town social activities.
Upon first arriving, Willie expects that Tom will be just as abusive as his brutal mother, as that is all he knows. On his first day, Willie faints in his imagined fear that Tom is angry with him and is going to beat him with a fire poker. Tom opens a window and thrusts the boy's head out into the air. It brings Willie back to life, but also makes him vomit severely. Afterwards, his body seems more relaxed and Tom leaves him to sleep. When he wakes, Tom introduces him to Sammy, his dog, and shows him his bedroom. Willie has never had a bedroom to himself and is overwhelmed by Tom's generosity. Tom opens the letter Willie's mother has sent with him and is furious that she has included the belt she uses to beat him along with his meager possessions.
The following day, Tom discovers Willie cannot read or write and was bullied in school. He loves art but was never allowed to paint, as that is reserved for the literate children in his class. Tom takes him to see Dr. Little and is given witch hazel for the bruises and welts all over his body. Tom also orders clothes for him from the draper as well as a couple of surprise gifts for his birthday which is coming up in a few days time. For the first time in 40 years, Tom goes into the art shop to get surprise gifts for Willie's birthday. Tom's wife Rachel had loved to paint and thus it takes a great deal of willpower for him to go back into a shop full of so many memories from the past. It takes some time for Willie to adjust to his new surroundings, still traumatized from his mother's abuse. Every night, he wets his bed, which makes him feel ashamed. Tom, who has inferred about Willie's past of abuse, reassures him it is a normal part of adjusting to his new life.
Willie meets a boy his own age called Zach, also an evacuee, who is living with the doctor and his wife. He arrives in time to help Tom and Willie construct their Anderson shelter in case of a German attack. Unlike Willie, Zach is confident and boisterous and highly overdramatic. Willie is shocked that Zach likes him and even more surprised when he asks to come back over tomorrow. Another boy, George, also turns up and asks them to join him and the twins, Carrie and Ginnie, for blackberry picking. At first, George and the twins seem not too keen on the idea of spending time with "townees," but slowly the children end up warming up to each other and have a wonderful afternoon. Willie is surprised but happy to make friends so easily, as his mother always told him that he was unlikeable.
School begins for the year and there is an influx of evacuees, making it much more crowded than usual. There, Willie is mortified to admit that he is illiterate, and he is placed with Mrs. Black, the teacher of the younger children, while Zach and his other friends go to Mrs. Hartridge's class. After school, Willie asks Tom to teach him to read and write so he can join the rest of the children his age. Zach, George, and the twins stop by that evening and share that they still wish to be friends with Willie, even though he is not in their class.
Before his first week is over, Willie is growing to love Little Weirwold. He is shocked to receive birthday gifts from Tom and some of the other villagers and delighted when a surprise party is thrown by Tom that evening. He begins to grow in confidence and his reading is also improving. He is also practicing his art and finds that he has an exceptional gift in drawing. The friends fall into a routine of spending time together and playing games. One day, Willie has them all over to his room. He shows them his artwork and they are in awe of his talent. Zach announces that Miss Thorne is producing a children's Christmas show and needs all the help she can get. Willie volunteers to paint scenery. George then announces there's to be a carol service at church, boys only, which infuriates Carrie who hates the stereotypical activities open to girls. That night after having his friends over, Willie realizes that for the first time since arriving in Weirwold, he has not wet the bed.
By November, most evacuees have returned to London, which poses a problem for the play director, Miss Thorne, as she has to keep re-casting roles for the Christmas show, "A Christmas Carol." Willie takes over as prompter after finishing the scenery and after a week he knows most of the play by heart. When he is asked to fill in for someone, he turns out to be an incredibly talented actor, even impressing Zach. Miss Thorne needs a new actor to take on the role of Scrooge and gives the part to Willie. Tom also steps up to fill in for Mr. Bush, who is called to war, to play the organ for the men's choir. He has not played in a very long time as it reminds him of his wife. Thus, both Willie and Tom are faced with a new opportunity to come more into the spotlight.
Willie finally reaches the standard of reading and writing required to join his friends in Miss Hartridge's class. There, rather than struggling, he actually performs very well, much to everyone's surprise. Carrie, a top student in the class, requests to take the exam so she can attend high school.
Will's happy life is halted in March when a letter arrives from his mother, informing him that she is sick and wants him to return to London. Willie dreads returning. He takes the London train and finds his mother waiting for him on the platform. He looks so different that she barely recognizes him. She is angered to see him relaxed and smiling and fears this is a threat to her authority. She then tells him she has a surprise back at the house. The surprise is more of a shock: Willie now has a baby sister, who has been left in a wooden box, with tape over its mouth to stop her from crying. As Willie shows his mother gifts and his artwork, she grows progressively more angry, believing that he has stolen these things, unable to believe that her son could have done anything good. She ends up hitting him across the head with a heavy object. He wakes up later to find himself locked under the stairs, beaten and bloody. He feels dissociated from the old part of himself, the abused Willie. Through his happy experiences in Weirwold, he now knows his real self, Will.
Tom misses William terribly and is concerned when he does not receive a postcard from him. After a disturbing, violent nightmare about being locked in a confined space, Tom decides to go to London to find Willie. In Willie's poor neighborhood of Deptford, the fire warden takes him under his wing and through the chance encountering of Mrs. Beech's neighbor, they are brought to Willie's house. The house seems empty but Sammy is frantically scratching at the door, indicating that Willie is inside. With the permission of a policeman, they break down the door. The vile odor inside sends them reeling and Sammy runs to a tiny door under the stairway where the smell is at its worst. They open the hole and find Willie tied to a length of copper piping, sitting in his own urine and excrement, holding a baby in his arms. Tom comforts him and takes the baby, which is dead. Willie is in a bad condition and they take him to the hospital.
At the hospital, Willie is treated, but he is being pumped full of sedative injections, forced upon him by the nursing staff. Tom learns their plan is to send him to an orphanage and he hatches a plan of his own, based on an imaginative message from Rachel. He waits for nighttime, when the nurse on duty is asleep, and he carries Willie off in a blanket. They journey back to Little Weirwold.
Back in Weirwold, Will takes time to adjust after his terrible abuse. He has horrendous nightmares and feverish sleep. Tom sits by his bedside to comfort him when he screams. After a few weeks, his sleep becomes calmer and Willie goes back to normal, seeing all of his friends, especially Zach. Tom, Will, and Zach take a trip to the seaside, where they stay at a bed and breakfast and spend their days on the beach and exploring the little shops. Willie is soothed by the ocean and even learns how to swim. When they return, they are greeted by an excited Carrie, who announces she has been accepted into the high school.
The last weekend of August, the children decide to pay a visit to Spooky Cott, an abandoned cottage rumored to be haunted. There, Will and Zach end up meeting a young man named Geoffrey. Geoffrey has left London after having his left leg amputated and losing one of his ears. He has also lost his fiancee, family, and best friend. Traumatized, he has holed himself up in the old cottage to get away from the world. Geoffrey is an artist and offers to give Will art lessons. His sadness is also lifted when he learns there is a prospect of teaching at the local school.
Will gets home that evening to find that the authorities from London have come to Tom's house. They inform Will that his mother has committed suicide and they want to put him in a children's home where he can be adopted by foster parents. He adamantly refuses and tells them he must stay with Tom, who loves him. Tom manages to convince them that the boy would do best with him. Finally, they agree to let Tom adopt Will. Tom and Will are both elated and dance around in celebration.
Zach receives news that his father has been gravely injured in the heavy bombings. He decides to return to London for the weekend to see his father. Before he leaves, he gives Will a birthday present of art supplies and a portrait he has drawn of Will. As the days pass with no word from Zach, everyone in town grows worried. After church on Sunday, they hear a radio broadcast relaying the news that an estimated 400 people were killed in air attacks in London. A couple of days later, Will is informed that Zach is among the dead.
Will does not deal well with his loss, avoiding every place that reminds him of Zach and finding himself unable to paint because he feels empty inside. Carrie is also finding the loss hard to bear. During an art lesson, Geoffrey shows Will a photo of his own best friend who died, explaining he smokes his friend's pipe because he feels close to him again. Will feels his grief come to the surface and goes to the river to process his emotions. Eventually, he begins to feel better and even starts riding Zach's old bike in order to honor his friend.
Once Will has accepted Zach's death, others begin to notice that Will is becoming more and more like the extroverted Zach. Miss Thorne wants Will to play Peter Pan in their upcoming show, but instead, he asks to play the flamboyant Captain Hook. He is a huge success and that night, with the applause still ringing in his ears, he realizes that he is truly happy and very glad to be alive. He realizes how far he has come. At home, when he hangs up his jacket on the peg, he finds that it is now too low for him and he announces to Tom - whom he now calls Dad - that finally he is growing.
