After a divorce and a failed suicide attempt, Archie Jones tries to start over by marrying the much younger Clara Bowden. However, he quickly retreats into his bachelorhood lifestyle, spending all his time at O'Connell's with his friend Samad Iqbal. Archie Jones is a practical rather than an intellectual man, a follower rather than a leader. He spends nearly 50 years carrying an enormous secret: the shrapnel in his leg is the result of his encounter with Dr. Marc-Pierre Perret in 1945, who shot Archie after Archie failed to kill him. In 1992 when Dr. Marc-Pierre Perret appears at the FutureMouse exhibition with Marcus Chalfen, Archie instinctively steps in the way of the bullet that Millat Iqbal intends for Perret, saving the man's life a second time.
Samad Iqbal, whose hand was crippled by friendly fire in the military, is disappointed the war afforded him no opportunity to live up to the legacy of his hero, his ancestor Mangal Pande. After he leaves Bangladesh with his young wife, Alsana, Samad becomes an increasingly devout Muslim as a way of resisting the corrupting force of British culture. His attempt to provide a traditional upbringing for his son, Magid, fails when Magid becomes an atheist and an intellectual even though Samad has sent him to live in Bangladesh. Samad increasingly regards his life as a failure; he loathes the West, but he made the mistake of moving there. When he discovers that Archie Jones didn't in fact kill Dr. Marc-Pierre Perret in 1945, as Samad believed for nearly 50 years, Samad is thrilled by this sudden discovery of his best friend's unexpected complexity.
Clara Jones is Archie Jones's second wife, a tall, beautiful Jamaican woman who wears false teeth, having lost her top teeth in a motorcycle accident when she was a teenager. Young Clara was a devout Jehovah's Witness like her mother, Hortense, but she rejects this religion after meeting some secular peers. Her mother disowns her for marrying a white man, and Clara works to lose her Jamaican accent. After giving birth to her daughter, Irie, Clara begins to educate herself about feminism, imperialism, and other progressive matters, eventually pursuing her studies at a university.
A member of a prominent Bengali family, Alsana Iqbal is in an arranged marriage with her husband, Samad, and immigrates to England with him in 1973. Alsana and Samad are constantly at odds and often use physical violence to settle their conflicts. Alsana rejects the modern Western obsession with self-revelation and endless talking about one's problems and feelings, as well as modern liberal morals, but she is a practical woman who steps out of traditional gender roles to meet the demands life in modern England places on her. When Samad secretly sends their son Magid off to Bangladesh, Alsana worries for his safety, knowing that natural disasters are common there. To punish Samad, she inflicts the uncertainty she must live with upon him by refusing to answer him with "yes" or "no." Until Magid returns home, Alsana drives Samad crazy by answering every question with "maybe."
When Magid is a preteen, his father sends him to rural Bangladesh, hoping to provide him with an upbringing free of the corrupting influence of Western culture. Magid's studious nature and prodigal intelligence earn him the attention of prominent Indian intellectuals, and to Samad's great disappointment, he decides he wants to become a lawyer, to help the East achieve Western-style progress. He becomes pen pals with Marcus Chalfen and, upon returning to England, lives with Chalfen, assisting him with all phases of the FutureMouse project. After his return, Magid's family regards his dignified bearing and his odd formality with suspicion, but Magid is unaffected by their hostility. He is an atheist who finds meaning in rational disciplines such as science and mathematics, and considers the certainty embodied in FutureMouse to be godlike.
Millat Iqbal, regarded by his family as "the troubled son," struggles with anger, identity issues, and feelings of being alienated from and rejected by dominant British society. As a young teenager, he is a promiscuous, drug-using heartthrob and the leader of a gang of similarly disaffected immigrant boys. Joyce Chalfen becomes taken with Millat, and he exploits her goodwill for his own advantage while she attempts to "save" him. Millat's search for belonging leads him to join the radical Islamist group KEVIN, but he struggles with the requirements of being a devout Muslim. Millat idolizes the gangster lifestyle and finds some expression for these violent urges in KEVIN. He longs to fight against the West and becomes disgusted when KEVIN abandons violence for pacifism. Vowing to overturn the course of history by succeeding where his ancestor Mangal Pande failed, Millat brings a gun to the FutureMouse event, intending to shoot Marcus Chalfen. However, his intentions are foiled when Archie Jones steps in the path of Millat's bullet.
As a teenager, Irie Jones struggles with self-hatred brought on by the realization that her Jamaican features don't conform to British standards of beauty. She is taken with the Chalfens, but Marcus Chalfen thinks Irie is incapable of understanding his scientific research and employs her as his secretary. When her chance discovery of her mother's false teeth makes Irie feel betrayed by her family's penchant for secrecy and half-truths, she goes to live with her grandmother, Hortense. Irie finds Hortense's religious obsessions amusing, but it is while living at Hortense's house that Irie discovers family photographs and other artifacts that allow her, for the first time, to develop a sense of her own roots and an idyllic conception of Jamaica, the place where her family came from. After having been in love with Millat Iqbal for years, she finally sleeps with him. When Millat responds with horror, Irie goes to seduce his twin brother, Magid. She becomes pregnant, and struggles with the realization that science cannot identify the father of her unborn child. Irie raises her daughter to believe Magid and Millat are both uncles. She visits Jamaica with her grandmother, daughter, and lover, Joshua Chalfen, in 1999.