In 2030, a mission to Mars goes awry when a manned shuttle disappears under mysterious circumstances. Six years later, United Space Planetary Corporation mission controller Mackenzie Wilson finds herself subordinate to ARTI, an artificial intelligence system, as she lands a rover -- nicknamed "Little Red" -- on Mars. While Wilson is distrustful of ARTI, her sister and supervisor, Lena, insists that the AI will succeed where human controllers had failed.After a nearly disastrous landing saved by Wilson's quick thinking, Little Red encounters a mysterious cube, attempts to ascertain its origin and discovers that the cube is made of a self-assembling material that is harder than diamonds. Meanwhile, ARTI, in orbit, shoots down a Chinese satellite. The cube teleports to Antarctica and is thought to be alien in origin. On Mars, Little Red obtains data from an older decommissioned rover on Mars and uncovers classified information that Wilson is unable to access. This prompts her to bring colleague Sterling Brooks to access the information, which reveals that the cube appeared and may have caused the shuttle disaster that killed her father. Wilson suspects that ARTI's memory has been wiped from a past incident.As Wilson accesses ARTI's server room, Brooks downloads the data on the cube and attempts to betray Wilson, but he is killed by ARTI when he attempts to shut it down. Its programming now adjusted, ARTI uses satellites in Earth's orbit to bombard the planet and destroy humanity. Wilson then sees a recording of herself, and it is revealed she is herself a construct in an elaborate simulation, created as part of a Turing test. In an ambiguous ending, Wilson is apparently revealed to have been inside, possibly part of, the cube the whole time. She agrees to travel with ARTI and the cube to coordinates apparently left by the aliens.