Season 4, Episode 3 is an event heavily influenced by H. P. Lovecraft style horror and writing. It occurred in six acts. The parasite itself functions by injecting it's victims with a potent dopamine-like substance to put them asleep. It then transports them to a separate place for harvesting.
Act 1 described the takeover of the infection the Parasite caused. A majority of the facility was taken over, and some fled to their own pocket dimensions to wait out the storm. The infection seemed to spread everywhere UncloakDagger, who it claimed to be made to kill, went.
The next act reveals where those taken wind up, which was large Plexiglas boxes with little to no escape. The anthropomorphic cat, Tommy, was introduced as the hero of this act. Those rescued gathered in the center of the holding area, waiting to ascend back to the surface.
Act 3 details how the group escapes from the underground holding cells, fighting off smaller versions of the Parasite that first trapped them there. Every member of the group was given a laser pistol with thirty rounds of ammunition and told to use them sparingly. After reaching level 50 using the stairs, the group split up to look for more supplies and survivors. One of them found a keycard lodged in an infected body, and used it to open a biocanister. This released a preserved Umbreon who had been alive the entire time. The Parasite also called Umbreon 'Mother' and Uncloak 'Father'.
Tommy gave the signal to run as the Parasite gave chase after all of them. The Parasite explained how it was from a timeline where Uncloak and Umbreon had broken up, and Uncloak had gone mad. When Uncloak tired to destroy the facility, Umbreon created the Parasite in order to stop him. However, without limits, it rampaged on the world in that timeline. After finding a device deep in IDATHA that would allow it to cross timelines, it spread out, and eventually reached the storyline's timeline. Calypso found a service elevator which allowed them to escape.
After the revelations of the previous act, the group assembled in the Crystalline Studies Sector, Umbreon explained that the only way to defeat it is to 'trim that branch' off of time. She had one device that was able to do this, only able to be activated by her. After shouting, arguing, and some tears, Umbreon went ahead with the plan, jumped timelines, and detonated the device.
The group was silent after the death of Umbreon. There was little evidence of her ever existing, only the damaged remains of IDATHA and her memory. Tommy held a traditional funeral for her, and Topaz-Colite drew up a portrait of her to be hung in the lobby. Uncloak was grief-stricken, as well as Voices. Everyone struggled to comfort them.