Logan’s Run takes place in the year 2274. What’s left of human civilization lives in a utopian city sealed in a cluster of geodesic domes. A supercomputer controls all aspects of life, death, and reproduction.
While its citizens live a hedonistic life, to prevent overpopulation, everyone must undergo the rite of Carrousel once they hit the age of 30. During this ceremony, the computer kills them under the pretense of being renewed.
To keep track of everyone’s age, each person receives a life clock, implanted at birth in the palm of the hand. It changes color the older one gets—only to begin blinking as they approach their Last Day.
While most citizens accept their chance for rebirth, those who do not and decide to flee the city are known as Runners. When this happens, an agency of the city called Deep Sleep, sends its elite team of policemen known as Sandmen to terminate Runners before they get too far.
We meet Logan 5 and Francis 7—both are Sandmen. After terminating a Runner fleeing his Carrousel rite, Logan finds an ankh among his possessions. Later that evening, he meets Jessica 6 who is a young woman also wearing an ankh pendant.
Curious, Logan takes his ankh to the computer which reveals that it’s a symbol for a secret group of people who help Runners find the Sanctuary—a mythic place where all who enter are safe to live out the rest of their lives in peace. The Sandmen have lost 1,056 Runners to this place.
Unexpectedly, the computer orders Logan to find Sanctuary and destroy it. It sends him on a mission codenamed Procedure 033-03 which he also must keep secret from the other Sandmen. The computer then retrograms Logan’s life clock to flashing red.
Now, Logan must become a Runner if he is to survive, (and complete his mission). After he explains his situation to Jessica, she takes him to an underground group that leads them to the outskirts of the city. Logan learns that the ankh symbol is a key with the ability to unlock an exit from the city.
As they exit it, they find themselves in a frozen cave with Francis in hot pursuit. In the cave, they meet a robot named Box which is designed to capture food for the city. Unfortunately, Logan also learns that Box captures escaped Runners which it freezes for food. However, before Box can freeze Logan and Jessica, they cause the cave to collapse on the robot, and escape.
Once outside, Logan and Jessica find their life clocks no longer operate, and they see the Sun for the first time in their lives. They find what is left of human civilization has returned to nature with ruins scattered about. They set out into what was once Washington, D.C., but find it’s not as abandoned as they thought it would be.
Once inside the ruins of the United States’ Senate chamber, they discover an old man living with his many cats. His appearance shocks them as neither have ever seen anyone over the age of thirty. As the old man recounts his memories of humanity’s fate outside the city, Logan realizes that Sanctuary was never a real place.
By now, Francis catches up to them, and he confronts Logan. Logan gets the better of Francis, and mortally wounds him. As he dies, he sees Logan’s life clock is now clear. He then assumes Logan has renewed.
Logan and Jessica then convince the old man to return to the city as proof life exists outside the domed city. They leave him outside before attempting to convince everyone that Carrousel is unnecessary. However, other Sandmen show up, and capture them. They then take the prisoners to the computer.
Once there, the computer asks Logan about Procedure 033-03. It wants to know if he completed his mission. Logan says that there isn’t a Sanctuary. He tells it that he only found scattered ruins and an old man. Any missing Runners, Box froze long ago.
Unfortunately, the computer doesn’t accept his answers, and decides to scan Logan’s mind. This causes the computer to overload and crash—causing all city’s systems to fail. This causes the exterior seals to open up, and Logan, Jessica, and the other citizens flee the city which is collapsing around them.
Once outside, the citizens meet the old man who is the first human they too have met who is older than thirty. This is all the proof they need to believe they too can live much longer than what they have been told all these years.