Anu Station is a large space station situated in a largely-unexplored solar system, in orbit around a planet with the designation
UP-2136-188b, which has been flagged as having environmental conditions
ideal for the development of life. The station plays host to rotating teams of scientists from various fields and specialties. One of these outfits is
Cassius Mining Corporation, which has
interest in mining rare earth minerals for use back on Earth. Corporate presence on the station is
somewhat controversial, but station commander Anton Greenspan is
committed to fostering an environment that's inclusive towards scientists from the private secor.
While
aware that caution must be taken due to UP-2136-188b's status as a planet that could potentially harbor life,
a manned survey mission is sent down to analyze potential mining sites. During the mission, surveyor Baltasar Stefansson
wanders off on his own for several hours. While he's gone, the rest of the survey team encounters the planet's dominant intelligent species: a race of telepathic shapeshifters. Alarmed by the presence of unwanted visitors and sensing their interest in mining, the aliens kill the survey team and take on their forms, intending to hitch a ride back to their place of origin in order to continue investigating the threat that they pose. Stefansson returns to the group, unaware of what has gone down in his absence, and assuming that the team's strange behavior afterwards is due to
anger over him having split off from the group. (The
general distain with which the rest of the station crew views his actions does nothing to dispel this.)
While laying low and posing as crewmembers, the aliens
do what they can to learn about the station's purpose and its intentions towards their planet,
sharing information with each other as they go. They learn that
Commander Greenspan's form would be useful to them, both for the purposes of information-gathering and (if necessary) controlling/influencing the crew away from an ill intentions towards their planet. They
kill Greenspan so that they can use his likeness with impunity, without risk of interference from the genuine article.
While
some crewmembers note the strange behavior of the returned survey crew, things only come to a head when an alien posing as Greenspan orders the entire population of the station to congregate in C Wing - this, the aliens have decided, is the best way to contain and control everyone while they try to figure out next steps. While
many are irritated,
confused, or
outright suspicious,
everyone does ultimately do as they're told (with a little urging from
undercover aliens). Some
forward-thinking members of the ship's security crew choose to arm themselves before following the commander's orders. Once everyone is inside, communications are disabled, and Greenspan's emergency lock keycard is used to
seal C Wing.
And we all know
what happens after that.