IF ANY OF U IS CRAZY ABOUT HORROR GAMES THEN OUTLAST IS THE ONE FOR YOU.

Miles Upshur, a freelance investigative journalist, receives an anonymous tip from a source identified only as a whistleblower. The lead tells of inhumane experiments committed at Mount Massive Asylum, a remote psychiatric hospital situated deep in the mountains of Lake County, Colorado and owned by the Murkoff Corporation, who is known for its corrupt dealings. Entering the asylum, Upshur is horrified to discover the mutilated corpses of the staff, including a dying SWAT officer who warns him to get out while he still can. As he investigates further, Upshur finds the asylum's patients, known as "Variants", freely roaming the grounds and hostile towards him, particularly a hulking sadist named Chris Walker. Approached by Martin Archimbaud, a cult leader who considers himself a priest, Upshur is told he was sent by "God" to be his witness to the night's events. It soon becomes clear that Archimbaud has no intention of letting Miles escape, and that he worships a seemingly supernatural entity known only as The Walrider, which he claims caused the breakout.

Trapped inside, Upshur is forced to work his way through Mount Massive and evade several Variants, including a pursuing Walker, and a pair of cannibalistic twins. Chased through the male wards, Upshur is rescued by a descending dumbwaiter, only to be captured by his savior, a delusional Murkoff executive named Richard "Rick" Trager. Trager, a "doctor" who experiments on patients, straps Upshur to a wheelchair and amputates two of his fingers. Left briefly alone, Miles manages to escape into an elevator. Grabbed by Trager while the elevator is still moving, a struggle ensues which results in Trager being crushed between floors. Upshur then encounters Archimbaud again along with The Walrider, which Upshur can only see through in IR mode. Reaching an auditorium with a playing reel, Upshur learns The Walrider was created by Dr. Rudolf Gustav Wernicke, a German scientist taken in by Operation Paperclip. Wernicke was developing a "Morphogenic Engine" for Nazi Germany, which employs severe psychological trauma and dream therapy to generate a malevolent nanite-driven being.

Finding Martin in the asylum's chapel, Upshur witnesses his self-immolation on a crucifix. Told he can escape by an elevator, Upshur uses it, only to be tricked and descends into an underground facility beneath the institution. Followed and attacked by Walker, Upshur watches as The Walrider gruesomely murders him. Locating an aged Dr. Wernicke, Upshur learns The Walrider is a result of nanotechnology experiments, and that it is being "hosted" by catatonic patient Billy Hope. Instructed to shut off Hope's life support system, Upshur does so, but is immediately seized by the weakened and hostless Walrider. Nearing death, he staggers towards the exit, where a security team led by Wernicke fires upon him. As Upshur collapses, Wernicke realizes that Miles is the Walrider's new host, and panicked screams and gunshots are heard as the screen fades to black and the credits roll.