Geo is a maintenance engineer on a large space station in a backwater system. His job is to keep the station up and running so that it can be used by ships navigating hyperspace. He's to do that all by himself. His only companion for the last eight years is a snarky station AI named Cotora who he is constantly at battle with. He would never admit it, but she's the only one keeping him somewhat sane.

Things change when a cargo ship tumbles out of hyperspace on a collision course with the station. With some quick thinking he is able to save both the station and the damaged ship, but there are people on the cargo ship which isn't normal. He sends a shuttle to rescue them and as soon as they're on the station, everything goes to hell for Geo. He is forced to play an AR game by those he saved.

Now he has to fight through the station's twenty-five floors which are filled with deadly creatures and strange worlds. He was lonely, but not lonely enough to want this.