In the afterword of 11/22/63, Stephen King states that Time and Again is "in this writer’s humble opinion, the great time-travel story.

In November 1970, Simon Morley, an advertising sketch artist, is approached by U.S. Army Major Ruben Prien to participate in a secret government project.

He is taken to a huge warehouse on the West Side of Manhattan, where he views what seem to be movie sets, with people acting on them.

As it turns out, Simon (usually called Si) has a good reason to want to go back to the past—his girlfriend, Kate, has a mystery linked to New York City in 1882.

She has a letter dated from that year, mailed to an Andrew Carmody (a fictional minor figure who was associated with Grover Cleveland).

Danziger, head of the project, agrees, and expresses his regret that he can't go with Si, because he would love to see his parents' first meeting, which also occurred in New York City in 1882.

He is accepted, begins living there and learns that the man who mailed the letter is named Jake Pickering.

Eventually, Pickering makes a scene, having tattooed the name "JULIA" on himself, and Si soon leaves, to return to the present.

After watching the efforts to fight the fire, in which many die, the shaken couple returns to Gramercy Park.

After they leave, Byrnes feigns indecision and lets them walk away—only to yell "The prisoners are escaping" to the sergeant who accompanies him.

(Again, the arm standing in Madison Square Park prior to the statue as a whole being erected is a factual event).

She is soon convinced otherwise, as Si brings them both into the present, and she observes the dawn from high inside the long-assembled statue, seeing a totally strange New York.

They spend a day in the present, with a shocked Julia observing the things that have changed in ninety years, from clothing to television.

He is ashamed to tell her the history of what has happened in the past ninety years, the horrible wars and the fact that there are areas of the city where no law-abiding citizen can safely go.

The two realize that the man whom they met at Carmody's house was in fact Pickering, who they could not identify because of the burns and bandages—Carmody had actually died in the fire.

The military men now in effective control of the project conclude that if Pickering is exposed, he might never have influence with Cleveland, and the U.S. might never have to worry about Fidel Castro.

On July 25 2012, it was announced that Lionsgate studios optioned the film rights to the novel, with Doug Liman set to direct and produce.