November 1930. The novel begins when Ursula Todd enters a café in Germany. She sits down next to Adolf Hitler, and has a short, polite conversation with him, until she pulls out a gun and shoots him. Ursula is then shot by his henchmen, and darkness falls.
Ursula is born in the Todd house (called Fox Corner) in a London suburb in February 1910. Her mother, Sylvie, and the Todds’ maid, Bridget, try to deliver the baby as best they can; both the town doctor, Dr. Fellowes, and the midwife, Mrs. Haddock, are stuck in a giant snow storm that has hit the town. Sylvie’s husband, Hugh, is also away, retrieving his rebellious sixteen-year-old sister, Izzie, from Paris, where she had become pregnant by her lover. When Ursula is born, her umbilical cord is wrapped around her throat, strangling her. She dies.
Ursula is born again in February 1910. This time, Dr. Fellowes arrives in time, and snips Ursula’s umbilical cord with surgical scissors, saving her. Ursula grows up, but experiences a variety of deaths when she is young, and is reborn in the same circumstances each time afterward. When she is four years old, she goes to the beach with her family and is led into rough waters by her older sister Pamela and drowns; in her next life, she is saved by a man painting by the water who notices the girls wade out into the ocean. When she is five, her older brother, Maurice, throws a doll of hers out of the bedroom window. She ventures out of the window, slips on ice, and flies off of the roof. In the next timeline, Bridget comes upstairs and stops her just in time.
Ursula also starts to get a sense of “déjà vu.” In each subsequent timeline a wave of terror washes over her before she takes the action that led to her death in a previous timeline. This allows her to try to actively avert certain disasters. For example, at the end of World War I, Bridget goes up to London to celebrate with her fiancé, Clarence, and catches the flu. When she returns, she passes the illness on to eight-year-old Ursula, who then dies. In the next timeline, she tries to avoid Bridget, but her younger brother Teddy catches the flu from Bridget and then passes it along to her. In her second attempt, she tries to prevent Bridget from reentering the house, leaving a note for her asking her to stay at Clarence’s house, but this is also thwarted. In her third attempt, Ursula pushes Bridget in the garden before she leaves, in the hopes that spraining her ankle will prevent her from going, but Bridget still decides to go. In the final attempt, she pushes Bridget down the stairs, breaking her arm and finally preventing her from catching the flu.
The narrative flashes forward from the end of World War I to the end of World War II, in February 1947. Ursula is living in London and has endured a long, hard war. Teddy is dead; the plane he was piloting went down in flames. Sylvie is also dead; her grief over Teddy led her to commit suicide. Ursula is also depressed by the loss of her younger brother. When the gas goes out in her building, she goes to sleep, knowing that if the gas comes back on, she will likely die. Darkness begins to fall on her.
Ten-year-old Ursula is introduced to a psychiatrist, Dr. Kellet, following the incident with Bridget and the stairs. When she talks about her déjà vu, he talks about reincarnation and fate, acknowledging that sometimes bad things have to happen in order to prevent worse things.
When Ursula is thirteen, she visits her aunt Izzie in London. Izzie is now an independent woman who writes a column about “modern women” in the newspaper. Izzie and Sylvie are completely at odds: Sylvie views Izzie as very irresponsible (because of her teenage pregnancy) and Izzie sees Sylvie as very traditional (because Sylvie views being a wife and mother as the most important thing a woman can be).
When Ursula turns sixteen, one of Maurice’s friends, Howie, kisses her very aggressively, and Ursula submits to this kiss, thinking that it is a rite of passage to becoming a woman. A few months later, when Howie is at Fox Corner again, he rapes her on the back staircase. Ursula doesn’t tell anyone, thinking that it must have been her fault. A few months later, she comes to the realization that she might be pregnant, even though she didn’t realize that that’s how babies are made. In a panic, thinking that she can’t tell her parents, she goes to Izzie’s apartment. Izzie says that they have to get rid of the baby, and takes Ursula to an abortion clinic (even though Ursula doesn’t fully understand what that entails). Following the surgery, Ursula ends up in the hospital. Hugh comes to support her and holds her hand as she recovers, but Sylvie is cold and uncaring, believing that the entire incident is her fault. After her abortion, Ursula doesn’t return to school, instead taking a typing course and moving to London. Also during this time, a neighbor of the Todds’, Nancy Shawcross, is murdered walking home. While living in London, Ursula meets Derek Oliphant and they begin a courtship. Derek offers her a sense of security, and they marry soon after. Derek quickly proves to be abusive, however, until one day he breaks her jaw and nose and sprains her arm. Ursula runs away, going once again to Izzie for refuge. She starts to recover from her injuries, but Derek finds her, and beats her to death.
In her next life, Ursula punches Howie in the face instead of allowing him to kiss her, thus avoiding the rest of that traumatic timeline. Additionally, because she avoids her abortion, she is able to walk Nancy home, preventing her murder as well.
The novel jumps forward in time, to the night before Britain declares war on Germany—the beginning of World War II. Ursula is involved with a married Admiral named Crighton and is working at the Home Office (Britain’s home security department). When the war begins, Crighton breaks things off with Ursula, and she starts seeing a young man named Ralph. A year into the war, Ursula is living in an apartment building on Argyll road that is directly hit by a bomb. A rescue team tries to save Ursula, but she dies from her injuries.
In the next version of her life, Crighton breaks things off with his wife instead of with Ursula, and she moves in with him during the war. But on the night of the bombing, she visits her old neighbors in Argyll Road and is caught up in the destruction once again. In Ursula’s third war experience, Ursula resolves to live out the war as a “nun.” On the night of the bombing, she grows lonely and sees a dog outside her window, and she rushes out to get him. She is saved from the bomb that hits the cellar, but instead she is crushed by a wall that falls on her in the blitz.
In Ursula’s next life, she takes a tour of Europe after university. Her travels take her to Germany, where she stays with a host family and witnesses the rise of the Nazi Party and Hitler. She marries a German man, Jürgen, and has a daughter named Frieda. Jürgen becomes a rising star in the Nazi party. As war looms, Ursula tries to return to England with her daughter, but Jürgen prevents her. Instead, she finds herself becoming friends with Hitler and his mistress, Eva Braun—even staying at their home in the country when Frieda falls ill. Five years later, Jürgen has died in a raid and the war is turning against Germany. Conditions are dire as Berlin is bombed and people are starving. Frieda becomes very ill, and Ursula realizes that the only way she can protect her daughter is by giving her a swift death. She gets two pills from the chemist, gives one to her daughter, and takes one herself. Ursula and Frieda die in each other’s arms.
In Ursula’s next life, she is back in England, except this time she has joined a rescue team that helps people during and after bombing incidents. The team has to deal with the horrible consequences of the bombs, as they see many limbless bodies, people with parts of their heads missing, and most tragically, babies who are crushed by the wreckage. Over the course of the war, Hugh dies of a heart attack, and Maurice informs Ursula that Teddy’s plane has gone down in flames and he is missing in action. Both of these incidents break Ursula’s heart, but Teddy’s death is particularly depressing to Ursula as she loved him more than anyone else in her life. Sylvie also takes an overdose of sleeping pills following Teddy’s death. By the end of the war, Ursula is emotionally and physically exhausted from her rescue missions and from the deaths of many of her friends in the squad and her family members. When the gas in Ursula’s building goes out, she goes to bed, but she wakes up before the gas turns back on, preventing her death. The narrative then jumps to 1967, when Ursula discusses with her nephew Nigel how the war might have been different if Hitler had been killed prior to the start of it.
Following this discussion, the narrative returns to Ursula’s birth. In this timeline, Sylvie raises the baby that Izzie had, named Roland, but he drowns in the ocean instead of Ursula. On her sixteenth birthday, Ursula is kissed by a different boy, Benjamin Cole, and they start a romance—but their romance leads inadvertently to Nancy’s murder once more because Ursula does not walk her home on the day she is murdered.
One day, when Ursula is having lunch with Izzie, she is struck by bouts of dread and heads to the street. She runs through neighborhoods she been in in her previous lives, becoming more and more conscious of these versions of her past. She falls and breaks her nose, meeting Derek Oliphant on the street before running away from him in terror. She eventually ends up in a sanatorium, discussing reincarnation with Dr. Kellet once more. Following this discussion, Ursula gains a clarity of purpose. She learns to shoot and studies German; she saves money to travel abroad. She meets seventeen-year-old Eva Braun in Munich long before Eva starts her relationship with Hitler. And then, in 1930, in a German café, Ursula shoots Hitler, and then is swiftly shot to death herself.
In the penultimate chapter, Teddy is able to escape his burning plane and spends two years in Germany as a prisoner of war. When the war ends, he makes it back to England, and joyfully reunites with Ursula.
The final chapter returns once again to the date of Ursula’s birth, but it focuses on Mrs. Haddock, the midwife who was unable to make it to the house. She is in a pub, stuck in the snow, and the barkeep tells her that it is unlikely she’ll be going anywhere for a few days.