Mount Pleasant is a small mining town in south-western Pennsylvania. The town was also deeply religious and is led by its priest Jonathan Rose and his wife Jean. During the Invasion of the United States, half of the town was destroyed and infected, however, the other half remained intact with the community still there making this a Post-apocalyptic settlement.
At some point, the town was attacked by the Chimera and most of the population was either killed or infected. The Feral Chimera known as Satan played a large role in decimating the population, and since then the derelict town has been overrun by Leapers, Grims and Leeches. Many of the human remnants were sent to fight it, but all failed, resulting in terrible losses. The townsfolk became careful of their survival and fortified whatever part of the town they held. The people of Mount Pleasant decided to stay and were willing to die where they lived, believing that the lord had given them their land and that they were being tested by God. Jean Rose stated that a group of disillusioned people later decided to leave, but only to had made it a half mile outside of Mount Pleasant before they were killed by the Chimera.
Joseph Capelli and Dr. Malikov later arrived in Mount Pleasant just after Capelli shot down an Chimeran Dropship and only hope of using the town's train to travel to New York City. However, the train was inoperable and can only be repaired by Jonathan Rose, who was missing. Malikov sent Capelli to find Jonathan somewhere inside the village ruins which still infested with Grims, Leapers and Leaches. Capelli managed to fend off many feral Chimera as he eventually found and rescued Jonathan. They able to restore the power for the elevator power and descend deep into the coal mine as they were pursuing and attacked by the Satan that grazing Jonathan until it Joseph Capelli finally defeated it by shooting at the creature's eyes, threw some acetylene tanks inside the creature's mouth before he quickly fire at the tanks, creating explosion which blow up the upper portion of creature's head and killing the Satan. After defeating the burrowing Chimera and recovered Jonathan from the mine, Jonathan able to fixed the train and hopefully allowed Malikov and Capelli to get to reach New York City.
With the elimination of Satan and the destruction of the wormhole tower, it is likely that the town population recovered from their losses and cleared the town of all remaining Chimera.
- Mt. Pleasant is similar to Ravenholm from Half-life 2, as both are a mining town, the Grims are similar to zombies, and Jonathan Rose is similar to Father Grigori.
- A resident of Mount Pleasant can be seen playing on a musical instrument made of a Hybrid skull.