Plot points SOMA begins in 2015, when Simon gets into a car accident, he survives, but his girlfriend Ashley dies. A man has suffered brain damage, and due to persistent and unstoppable strange effects, he agrees to an experimental method of scanning his brain. He loses consciousness, after which he ends up in 2104 at a mysterious underwater station.

He finds out what happened. Simon learned that a year ago the Earth collided with a large comet that destroyed all life on the surface. The protagonist's consciousness is inserted into another body. Simon then learns that his body is a steel mechanism powered by structural gel. Elements built into his body are capable of connecting biological tissues with artificial fragments. Katherine is a scientist whom the protagonist meets, she is a similar copy of a real person. She asks the character to help in a difficult matter. He has to save a satellite where hundreds of thousands of data from all fake creatures are collected.

The gameplay is similar to Penumbra and Amnesia. The main emphasis in the passage is on the narrative. The user will have to navigate corridor locations and solve problems. While exploring the PATHOS-2 underwater stations, the ward will encounter monsters and deadly dangers. The user is not able to fight, only hide or run from enemies. Each monster has its own behavior and organ that allows it to sense its surroundings.