Penumbra: Black Plague is the second installment of the Penumbra series of episodic games for the PC developed by Swedish developer Frictional Games. The story continues where the previous episode, Penumbra: Overture, left off. It was released on February 12, 2008. First intended as a trilogy, the series was reduced to two episodes due to unidentified problems with the previous publisher, Lexicon Entertainment, with the announcement of Penumbra: Black Plague. This episode was published by Paradox Interactive. However, Frictional Games has announced that Penumbra will get an expansion named _Requiem.
Like the previous episode, Penumbra: Overture, Black Plague is an exploration-based adventure game that takes place from a fully 3-dimensional, first-person perspective. Although the game is presented as a first-person adventure game, it also contains elements of first-person shooter and survival horror gameplay.
Gameplay features a mixture of exploration and solving physical puzzles (the Newton Physics engine allows for many physics puzzles similar to those seen in Half-Life 2). In comparison to the previous episode, combat has been heavily de-emphasized. Players will no longer be able to acquire melee weapons or create makeshift traps to fight enemies with. Instead, the emphasis is on the use of stealth and fleeing to avoid attacks by enemy creatures.
Continuing from where the previous episode left off, Philip wakes up in a small cell. After finding a way out from his prison, he finds some hints that his father Howard might still be alive in this underground laboratory. However, Philip also realised that he might not be alone in this hostile underworld...
During his exploration through the underground facility Philip also has to battle against the voices inside his head while avoiding the traps and infected creatures that want to kill him.
The story of Black Plague begins as an email sent by Phillip to a friend, explaining what has happened to him and begging him to finish the work he could not. The rest of the game then proceeds as a flashback narrated by Phillip to his friend in the email.
The game begins with Phillip waking up in a locked room, after being knocked out by an unseen being at the end of the first game. Phillip manages to escape via a nearby air-vent, and finds himself in the underground research facility of the Archaic Elevated Caste, a secret organization dedicated to discovering and researching ancient knowledge. The base is abandoned and in ruins, with all its personnel either dead or transformed into "the Infected", fast, zombie-like creatures that attack Phillip on sight.
Phillip discovers that he has also been infected; however, his reaction to the virus is extremely abnormal; instead of joining the infected hive-mind, Phillip instead develops a sarcastic, malevolent split-personality that calls itself Clarence (after the guardian angel from It's a Wonderful Life) who constantly taunts Phillip throughout the course of the game.
Via the base's computer network, Phillip is contacted by Amabel Swanson, an Archaic research scientist who has managed to survive the outbreak by locking herself in her lab. Swanson promises to help cure Phillip's infection, if he will make his way to her section of the facility and rescue her.
Through dialogue with Swanson, and various scattered documents found throughout the base, Phillip learns that the Archaic came to Greenland to look for the "Tuurngait", an ancient entity described in native Inuit mythology as primordial spirits native to the area. Penetrating deep underground, the Archaic found and released the Tuurngait, which manifested as a sentient virus that infected the base's personnel. Phillip discovers his father Howard managed to communicate with the Tuurngait, but what he learned drove him to commit suicide after sending Phillip a letter ordering him to destroy his research documents.
Phillip eventually manages to make his way to Amabel's lab, but Clarence causes him to hallucinate and murder Amabel. Using Amabel's lab notes, Phillip manages to rid himself of Clarence by extracting him using a lab machine. However, the machine transfers Clarence into a nearby corpse, which he reanimates and uses to attack Phillip.
Phillip is saved by the Tuurngait itself, as several Infected arrive to destroy Clarence, for Clarence now possess an individual body and mind rather than part of "the many" in Tuurngait. The Tuurngait communicates directly with Phillip, sending him into his own mind and putting him through a series of spiritual tests designed to test his ability to cooperate, show mercy, and demonstrate self-sacrifice.
Once Philip passes the tests, the Tuurngait reveals all; it is an ancient entity that came to Earth millions of years ago; it once co-existed peacefully alongside the native Inuit, using "Infected" host bodies to pass its ancient knowledge to mankind. However, in time mankind began to grow and expand, and the Tuurngait burrowed underground to separate itself from the human world. When the Archaic came, they disturbed the Tuurngait's ancient slumber and attempted to exploit it, and it fought back against them in self-defense.
The Tuurngait explains that mankind is great as a whole, but selfish, petty, and destructive as individuals. However, it believes that Philip is different from most of mankind. The Tuurngait puts itself at Philip's mercy, asking him to send a message to someone aboveground, for them to destroy the Archaic's research facility so that the Tuurngait may rest in peace. This is the same request the Tuurngait made of Philip's father Howard, however Philip thwarted it by coming to investigate instead of following his father's instructions.
Philip seemingly agrees to the Tuurngait's request, and sends an email to a friend on the surface describing his adventure. However, at the last moment, Philip reveals his desire to exercise his free will, instead of blindly obeying a higher power. Stating that he has more in common with Clarence than with the Tuurngait, Philip gives his friend the coordinates of the mine and tells him to come and destroy the Tuurngait. His last words are: "Kill them. Kill them all."
The game has taken some influence from H.P Lovecraft's Cthulhu Mythos with the long forgotten underground alien creatures somewhere in the Antarctic. Also the main protagonist's name is Phillip, and his father's name is Howard, both probable homages to the author's first and middle names. The format of the story is also very Lovecraftian; it is a flashback narrative given by a doomed narrator, warning others of the horrors he has discovered.