The Andromeda Strain is a 1969 science fiction novel by Michael Crichton. The book tells the story of the Wildfire Project, an initiative to investigate a mysterious alien organism discovered in Arizona. The Andromeda Strain has been adapted for film and television. It was highly praised by critics on release and credited with creating the techno-thriller genre.

Plot Summary

A military team is dispatched to recover a satellite that unexpectedly crashed to Earth near Piedmont, Arizona. Everyone in the small town has been mysteriously killed, including the recovery team. The military activates the Wildfire Project, a scientific initiative to deal with potential alien life appearing on Earth. The satellite was designed to collect samples from the upper atmosphere and bring them back to Earth to be studied.

The Wildfire team is led by Jeremy Stone. He worries that a deadly alien organism has returned to Earth with the satellite, killing everyone in Piedmont. Stone and another team member named Burton travel to Piedmont in sterilized suits. They find everyone dead except for an old man named Peter Jackson and a baby. They recover the satellite capsule and take it and the survivors back to their top-secret base.

The Wildfire laboratory is designed to study alien organisms without contaminating the outside world. The underground facility has five layers of increasingly strict contamination measures, as well as a nuclear bomb placed below the base and programmed to detonate in the case of contamination. Two more scientists—Hall and Leavitt—arrive at the base. Hall has been a part of Wildfire for a year, but he has never taken it seriously. He is the only unmarried member of the team, and he was chosen for this reason. A fictional theory named the Odd Man Hypothesis suggests that single men can be best trusted to make a life-or-death decision. Hall is given a key that can avert the automatic destruction of the facility. In such an event, he must decide between saving himself and his colleagues and potentially allowing the contamination to escape, thus threatening the entire world.

The scientists pass through strict contamination procedures as they descend through the multilayered facility. They reach the most secure lab and run a series of experiments. They discover an alien organism on the satellite capsule, but it does not resemble any life as they know it. Exposing rats and monkeys to the organism results in death. The scientists autopsy the dead animals and test the samples in many ways, exhausting themselves in the process.

Hall interviews the old man who survived in Piedmont. He begins to believe that the acid levels in the human body may dictate whether a person can survive exposure to the organism. As the scientists work around the clock, day after day, they become tired. They make mistakes, either missing vital messages or failing to run essential tests. Their investigations run into dead ends, and they are no closer to understanding the nature of the organism, which is codenamed the Andromeda Strain.

While the scientists run their tests, the Andromeda Strain mutates into a new form that attacks rubber and plastics instead of humans. Outside the laboratory, this mutated strain is responsible for a plane crash. Inside the laboratory, the new strain begins to destroy the sealants that protect the scientists and isolate the organism from the rest of the world. The threat of contamination becomes real. Burton is exposed to the organism, but he does not die. Stone and Hall try to save Burton while Leavitt suffers from an epileptic seizure, a condition he hid from his colleagues.

The facility breaks down under the attack from the mutated Andromeda Strain. The nuclear weapon is armed, primed to detonate. The scientists realize that the explosion will not kill the alien organism but will actually make it stronger. Hall is sealed in a laboratory and so must break out and climb through service hatches to reach a key station, averting the explosion. He bypasses the security measures, such as tranquilizer darts and sedative gases, reaching the key station in time. Hall averts the explosion and saves the laboratory.

Afterward, Hall discovers that he saved his colleagues, but the Andromeda Strain escaped into the wider world. The organism migrates to the air above Los Angeles, where it appears to become benign, no longer a threat to humans. A short epilogue reveals an investigation is launched into a manned spaceflight that crashed mysteriously. The implication is that the Andromeda Strain was responsible. All future spaceflights are cancelled until an investigation conducted by a team including Stone allows spaceflights to resume.