Mary gives birth to a baby girl, and Tim knows he can never see his father again. Tim tells his father that he cannot visit any more, and together they travel back to relive a fond memory from Tim's early childhood.
He is reluctant because it means he will not be able to visit his father again. Tim follows this advice his father dies, but Tim travels to the past to visit whenever he misses him. He tells Tim to live each day twice in order to be truly happy: first, with all the everyday tensions and worries, but the second time noticing how sweet the world can be. His father has known for some time, traveling back in time to effectively extend his life and spend more time with his family. Tim learns his father has terminal cancer that time travel cannot change, as going back far enough would undo his relationships with Mary and Kit-Kat, something he is unwilling to do.
Tim and Mary have another child, a baby boy. She settles down with Tim's friend Jay and has a child of her own.
Tim accepts that he cannot change his sister's life by changing her past he allows the crash to occur, ensuring Posy's birth, and he and Mary help Kit Kat face her problems to improve her own life. James explains that they cannot change events prior to their children's birth and ensure that exact child will still be conceived. They manage to return to the present, where Tim finds Posy has never been born and he has a son instead. As Kit Kat recovers, Tim decides to intervene in her life: he prevents the crash and takes Kit Kat back in time to avert her unhappy relationship with Jimmy. Kit Kat's drinking habits lead her to crash her car on Posy's first birthday. He proposes they marry and have a daughter, Posy. One night, he encounters Charlotte who now seems interested in him, but Tim turns her down, realising that he is in love with Mary. Their relationship develops, and Tim moves in with Mary. Tim goes back in time and discovers when and where they met, turning up early before the potential boyfriend arrives, and persuades Mary to leave with him instead. However, he discovers that she now has a boyfriend. He recalls Mary's obsession with Kate Moss, and finds Mary a week later at a Kate Moss exhibition. However, when Tim tries to call Mary, he discovers that by going back in time to help Harry, the evening with Mary never occurred. Tim goes back in time to put things right, and the play is a triumph. Tim returns home to find a distraught Harry, whose opening night of his new play has been ruined by an actor forgetting his lines. They flirt in the darkness, and afterward, Mary gives Tim her phone number. Tim visits a Dans le Noir restaurant, where he meets Mary. Tim moves to London to pursue a career as a lawyer, living with his father's acquaintance, Harry, an angry misanthropic playwright. Heartbroken, Tim realises she is uninterested in him, and that time travel cannot change anyone's mind.
Tim travels back in time to tell Charlotte in the middle of the holiday, but she advises him to wait until her last day. Tim is instantly smitten, but waits until the end of her stay to tell her how he feels she tells him that he should have told her earlier. The following summer, Kit Kat's friend Charlotte visits. James discourages his son from using his gift to acquire money or fame, and Tim decides he will use it to improve his love life. On his 21st birthday, Tim learns from his father that the men of his family have the secret ability to travel back in time, to moments they have lived before. Tim Lake grows up in Cornwall, in a house by the sea with his father James, mother Mary, absent-minded uncle Desmond, and free-spirited sister Katherine ("Kit Kat").