Plot summary

In the year 2020 AD, a mission is launched whose goal is to carry humans to Mars for the first time. The mission's four crew members, upon arriving on the planet, discover a mysterious geologic formation in their vicinity. After transmitting their findings back to the command center on the World Space Station, they head for the site to try and learn more. When they arrive at the formation, they notice a strange sound, which they assume to be interference from their Mars Rover. While attempting to scan the formation with radar, a large vortex forms around the structure, which envelopes and kills two of the mission's crew. A third member was killed when a large rock breaks her visor, exposing her to the Martian atmosphere. Only the mission's commander, Luke Graham (Don Cheadle), survived. The formation also emits an extremely powerful EMP, which irreparably damages much of the electronic equipment on the spacecraft. Despite the damage, Luke Graham manages to upload one transmission to the REMO (REsupply MOdule) orbiting Mars.After receiving Commander Graham's garbled message informing of his crew-members' deaths, the Earth command center hastily dispatches another Mars mission. The crew of this new mission includes Commander Woodrow "Woody" Blake (Tim Robbins); Co-Commander Jim McConnell (Gary Sinise); and mission specialists Terri Fisher (Connie Nielsen) and Phil Ohlmyer (Jerry O'Connell). The goal of the mission is to investigate the tragedy and bring back any survivors. As the ship is being prepared for its orbital insertion around the red planet, a swarm of micrometeorites collides with the ship and compromises the ship's hull, causing an atmosphere leak. The crew works quickly to repair the hole, troubleshooting where the damage is located, and then using a liquid to help Woody apply the patch.Unbeknowst to the crew, the fuel tanks were also damaged, and when they ignite the main engines, the resulting fuel explosion destroys the ship. They quickly don pressure suits and abandon it, hoping to maneuver their way to the REMO. Circumstances are unfavorable, though, as the REMO is moving more quickly (in a slightly lower orbit) than the tethered astronauts. Woody concludes the only hope of a successful rendezvous with the REMO is for him to launch himself directly at it, using the remainder of his jet pack fuel, carrying a line from the others. He successfully attaches this to the REMO but is unable to stop himself as he does and floats helplessly away toward the planet. Terri, wanting to save him, decides to cut her line. Woody, not wanting Terri to be harmed, commits suicide by taking off his helmet.When the remaining crew arrive on the red planet, they find Luke, the captain of the first team, still alive. He tells the rescuers about his crew's findings, and informs them that the formation found was the "face". He had spent the time alone attempting to learn the secrets of the mysterious structure. He shows the rescue team his most significant clue, a recording of the noise heard in the area of the formation. He had found, after several months of analysis, that the sound was a map of human DNA, in XYZ coordinates.Together, they discover that the mysterious signals are actually a prompt, requiring input of one missing pair of chromosomes which would complete human DNA. The crew dispatches a robot to send the completed signal, at which time an opening appears in the side of the structure. Curious, they venture inside, and are soon sealed in, and discover Earth-like atmospheric conditions. They find a large dark room, and once they step inside, a three-dimensional projection of the solar system appears.A Martian appears, silently explaining that at some time in the distant past, Mars was hit by a "planet-killer" asteroid which decimated the Martian ecosystem. The Martians were forced to evacuate their home planet and find other places to settle. During their evacuation, however, they also dispatched elementary life forms of their own to the nearby planet Earth, which at the time of the Martian evacuation, contained no life forms. Over the billions of years following this "seed-scattering", these life forms eventually became the humans who would one day land on Mars and be recognized as descendants of that ancient Martian experiment.As the image of the Martian fades away, an invitation is offered for one of the astronauts to follow the Martians to one of their new home planets. Jim McConnell decides to go and after their farewells, the rest of the surviving crew head back to Earth. As they are heading toward earth they watch in curiosity as Jim inside a Martian craft races away at speeds hundreds of times faster than their ship.