Grace is a wife and mother who finds herself trapped in her own body when she awakens in a hospital. She can't open her eyes or move a finger. She yearns to scream, but is unable. Using every fiber of her will, she tries to move the heaviness of her inert body, until she finally slips free of it, emerging into the gleaming sterile whiteness of the room, where she gazes at her own comatose body as a doctor pries open her eyes. Addressing her husband, she explains how she became unconscious and unresponsive.

"It is difficult to decide what to praise most highly in AFTERWARDS. Should it be the people who live and breathe on these pages? The perfect pacing of the plot? The intriguing who-done-it puzzle? The ticking-clock urgency of Grace's quest to help her children?"

Grace remembers that it’s sports day at the school their son Adam attends. It also happens to be his eighth birthday. On this day, Grace's 17–year-old daughter, Jenny, has been assigned to work as the school nurse. Grace is horrified by this idea, saying it’s too much responsibility for a teen, but Jenny laughs off her fears, saying it's just a sports day, not a car race. She will be fine, up in the third-floor nurse's office. Grace is out on the Sidley House playing field watching the students run races when Adam asks if he can retrieve his birthday cake from inside the school. Rowena, the teenage daughter of Grace's friend Maisie, offers to go with him. While he’s gone, Grace watches for Jenny, who should arrive on the field any minute.

When Adam doesn't return immediately, Grace looks at the school building and sees thick black smoke pouring from it. Knowing her children are in danger, she races for the building. She is relieved to see that Adam is outside the school, being comforted by Rowena. Not seeing Jenny, though, she runs into the burning building, choking on the smoke and screaming her  name. She knows Jenny is on the third floor, so she fights her way through flames and smoke, climbing stairs until she finds her. Grace drags Jenny toward the school's doors, but before she can reach the bottom of the stairway, something hits her. She falls and everything goes black.

Now, in the hospital, watching her own body being worked on by medical personnel, Grace knows she must find Jenny again. She screams at doctors and nurses, demanding they tell her where her daughter is. No one can hear her. She is both invisible and silent to everyone else. Finally, Grace discovers Jenny in the emergency room, so badly burnt as to be unrecognizable. She only realizes this terribly damaged patient is her daughter when she sees Jenny's sandals on the bed. When Grace shouts Jenny's name, she hears an answering voice. While medical staff wheel the stretcher with Jenny's physical body on it, she puts her arms around the Jenny who is crouched on the floor, asking, "What are we, Mum?" Grace doesn't know the answer to this question, but she doesn't have time to contemplate it. As she watches and listens, she discovers a terrible mystery that she must solve in order to protect her family.

Author Rosamund Lupton spins an unusual yet completely believable tale centered on a mother's determination to do whatever it takes to keep her kids safe, even though her body is incapacitated. It is difficult to decide what to praise most highly in AFTERWARDS. Should it be the people who live and breathe on these pages? The perfect pacing of the plot? The intriguing who-done-it puzzle? The ticking-clock urgency of Grace's quest to help her children? All of these elements work together in this marvelous page-turner, surely destined for many "Best Of" lists.