Locked in Time is a 1985 suspense novel by Lois Duncan. The story centers around Nore, a seventeen-year-old girl who moves into a new home with her father and her new stepfamily. Soon after she meets her stepmother, stepbrother, and stepsister for the first time, Nore begins to suspect something is not quite right about her stepfamily. The author states that the novel explores some of the issues surrounding having eternal life. Duncan says she developed the idea for the novel when one of her daughters was thirteen years old and was having issues with her body image. Duncan mentions that her daughter was "taking everything out" on her, and she began to wonder what it would be like if her daughter never outgrew her adolescence.