3 individuals wander around on the planet of Mars. David Tinkerman makes a remark that the planet, though called the "red planet" seems very brown. The other two—Leah Hamakawa and Tally—comment on this as well. However, what the three realize is that under the brown exterior, the landforms and terrain are actually multi-colored. Leah finds the land beautiful and begins to observe the dirt and rocks. Tinkerman follows her, but Tally explains that it is not beautiful and actually quite stinky. The three wear rebreathers that filter out air as there is no oxygen on the planet. Tally then explains that they need to leave because they need to determine the culprit of two murders rather than explore the planet.

After exploration, the three individuals return to their ship--named Albert Alligator. The pilot, Langevin, who greets them as soon as they enter, suddenly gags, and runs off. As the three take off their rebreathers, they realize how terrible they all smell. Leah works to take off her suit and Tinkerman goes to help her, wanting to get close to her.

Langevin lands the ship and creates a small house on the planet's surface--a temporary living space called the "habitat." He explains that the rover will be there in a few days for their use, as it is currently in transit from the moon.

The three enter the habitat and observe. There are two sleeping cubbies and Tally suggests that the women share one and Tinkerman has his own. Tinkerman speaks up, saying he would rather sleep with Leah and Leah doesn't seem to make any effort to agree or disagree.

The next day, the trio walks to a nearby habitat to observe the two murdered bodies. The bodies seemed to be eaten away by bacteria so only a few bones remained. They observe the fractured bones and conditions of the bodies and believe that someone killed them. However, there are no footprints nearby, so they keep hypothesizing.

Leah and Tinkerman are members of an incident investigation team and Tally is a freelance survival specialist--their source of protection. Tinkerman wonders why someone would murder two researchers as the planet itself is not very exciting. He explains that the planet was terraformed, but Leah immediately retorts, saying that the planet underwent ecopoiesis.

Many years ago, an engineer named Joseph Smith Kirkpatrick wanted to transform Mars. He and his team worked to erupt a volcano on the planet using lightning, which eventually created a giant ocean on Mars and an atmosphere. He also used bacteria to live in the atmosphere, as there was no oxygen. Tinkerman realizes that this bacteria is why the planet smells so bad. Eventually, this process created too much carbon dioxide. Later on, this process of ecopoiesis was debated in the scientific field. Kirkpatrick was put on trial and eventually died. Another man named Freehold Toynbee put a law on Mars saying that no one could travel there for the next billion years, but no one listened to this. He eventually went bankrupt. Many people tried to inhabit Mars for several years, but eventually no one was on Mars and they decided to go to other planets.

Tally explains that whomever murdered the two researchers didn't leave any bootprints. They speculate what could've killed them. Tally suggests it was a fight to the death between lovers while Tinkermran wonders if they were burned. Both theories are shut down by Leah. As they sit, Leah realizes that the three of them got sunburnt by the UV rays.

Later that night, Leah sits in a chair and explains to Tinkerman that the dead bodies frightened her. She cries into his arms.

Tinkerman recalls the first day he met Leah. He was teaching a class on troubleshooting and Leah was one of his students. She was a good student and incredibly smart. He invited her with him to visit Los Angeles--called Old Los Angeles (or OLA). She agrees to go with him, fascinated by the concept and the fact that he had a guide to show him around. OLA was the location of a virus that broke out many years ago. There were numerous labs and an ecosystem that formed as a result. The guide they had was named Tally Okumba.

When Tinkerman wakes up, he sees Tally dancing outside his window. Their task that day was to observe the shards of the shattered habitat of the two researchers. They notice the shards are very far away from each other, which Leah explains is from the wind. The two wonder if the habitat was destroyed because of an explosion and then the beams were bent by the wind. They conclude it has to be due to an exterior explosion.

When they return to their habitat, each member speculates about who caused the explosion. There are numerous individuals who are in favor of ecopoiesis and those who aren't, so perhaps the researchers made enemies. Yet, Tally, who explains she's seen many bombs, explains that there are no bomb remnants.

Tinkerman thinks about how he is never quite able to understand Leah's thoughts. She was very direct with her words, but never seemed to show much emotion. She notices him staring one day and asks if he wants to sleep with her. Tinkerman and Leah have sex, but she tells him that it doesn't mean anything to her, but it means a lot to Tinkerman.

The next day, they work on decoding the data and studying the wreckage. Leah realizes that from the sample she has, there is no steel, even though habitats do have some steel. As the head out to the field again, Leah wonders if the individuals that killed the researchers may be targeting them but Tally calms her nerves saying that they'd be able to see an attacker due to the barren wasteland terrain.

The next day, Leah realizes there is no steel because of the sulfur on the planet, which converts steel to iron. Tinkerman explains that the records he looked at explain that the last data recorded by the researchers was on August 10th. Leah responds saying that it is currently June 23rd and that in a few days, Mars will have completed a full year.

Leah sends Tinkerman out to observe the weather and he notices that the cloud coverage is a yearly event. The rover arrives soon after. Tally suggests the trio go to the ocean nearby. Leah and Tinkerman make the discovery that the methane in the atmosphere and bacteria are producing greenhouse gases making the planet more suitable for life.

The following day, Tally tells the two that she is going to stay behind and guard the habitat while they go to the beach. On the way there, in the rover, they stop for the night and sleep besides each other. Tally goes on radio silence because she does not like to answer the communication device often.

When the reach the ocean, Tinkerman notices that the ocean is white and boiling. However, Leah jumps into the water and explains that is lukewarm because the boiling is actually the fizzing of carbon dioxide. They both swim and take a bath in the water. When they go to sleep, Leah suddenly wakes up and begins to do research on her computer. She doesn't tell Tinkerman what she is writing down, but they begin their journey back to the habitat. She explains that the habitats are meant for the moon and that the exterior pressure of Mars caused the place to implode last time. This implosion cut through the oxygen tanks and the two researchers died of carbon dioxide poisoning and lack of oxygen. They hurry home in hope that Tally is still alive. The rover breaks down part way there so Leah and Tinkerman begin walking back to the habitat to find Tally still there. Tally explained that she noticed the difference in air pressure so she increased the pressure in the habitat, which ended up preventing the implosion.

On the last day of Mars, the three reflect on their discoveries and time there. Tally explains that she doesn't like it because it smells and Leah finds it beautiful. Later that night, Leah and Tinkerman make love again, and Tinkerman asks her if she feels anything for him. She dismisses it, saying it's a meaningless question, but she is also ok with being stuck with him. Tinkerman thinks about how meaningful that is to him and decides that he will continue to follow her, even after the trip is over.