fern ridge, a brilliant young scientific mind, was an astronaut & communications officer on a manned space mission around mars. his job specifically was investigating things outside the craft, so space walks, checking in with base, & the daily log. other crewmembers include aster chen, the captain, poppy copeland, sister of dahlia copeland, & a few other of the brightest minds of their generation, employed by the technocorporation NASA-X.

however, the spacecraft that fern left on & all of its crewmembers went radio silent some time after arriving in orbit of mars. NASA-X downplayed the vanishment & redacted the details of the last months of the mission.

a year after the mysterious vanishing of the ship, dahlia, desperate to know what happened to her sister poppy, has finally broken into the records of the ship's log. her in: a scientist named laurel munroe who worked on the mission. dahlia & laurel watch the ship's log recordings, & with fern narrating, dahlia watches the crew descend into intense paranoia. a popular delusion: aliens are onboard the ship, slowly replacing the crew.

through the recordings, it's soon revealed: this is no delusion. the sickness & paranoia invading the minds & bodies of the scorpion's crew is a result of a parasitic fungal infection that distantly resembles cordyceps, crawling into the brains of the infected. fern realizes this far too late, & the aggressive infected crewmates have already killed everyone uninfected except fern.

fern destroys the ship to eliminate the infection. however, they are again too late. their last message is like a plea to earth, because before they blew everything to hell, an escape pod launched, with the infected body of poppy copeland in it.

dahlia, back on earth, arrives at the landing site of the pod, & uses a shotgun to stop the shell of her sister.