In a darkened room, a journal reads: "They've left me. Everything was just a lie."In the year 2020, Frank Barrens, a middle-aged paraplegic, returns to his childhood home for the first time since his youth to probate his father's will after his demise. Upon returning home, Frank looks around the old house and rediscovers items of great significance from his time as a drummer for his high school band.During the Christmas holidays of 1990, Frank's cousin Suzie encourages him and his band mates Mike Astin and Jack Wilson to play paying gigs to hone their musical skill. Jack and Mike inform Suzie, who is from out of town, that one of their school classmates named Garrett Redmont has gone missing and families around town are nervous about kids being out late. Suzie talks the band into rehearsing at the Barrens' home after school anyway to Mike's reluctance.A few weeks later, Mike is on his way to Frank's house for rehearsal when he passes the "Grey House", an allegedly haunted house that sits between school and his destination. Mike hides when he hears Miller Thompson and Tucker Daniels, two of his school's bullies, approaching. However, when he overhears them talking about the recent disappearance of Redmont, he believes they may be involved and he follows them to the nearby woods. Once the bullies catch Mike following them, they scare him off after telling him not to let anyone know about his reconnaissance.Mike reconvenes with Suzie and Jack at Frank's house in time to find out that Jack found Redmont lying unconscious at their local library. After regaining his health and being dismissed from the hospital, Redmont joins the band at Frank's house to thank Jack for helping him. During the conversation, the band learns that Redmont's family is negligent of him, which explains the rumors that have spread about Redmont running away from home. Redmont denies these rumors, saying he has had amnesia of the entire disappearance.Realizing Redmont could use a helping hand, the band invites Redmont to stay for their rehearsal where Frank introduces himself to Redmont and informs the band that the owner of a local club called the Starlight has agreed to let them perform later that month.Suzie takes a tour of the town, videoing what she sees along the way with a camera Frank recently bought for her. While passing by the woods, Suzie passes a lone, young man carrying a pistol, contemplating suicide. In an attempt to dissuade the man from doing so, Suzie approaches the man, who introduces himself as a town local named Robert Grayson. Suzie encourages Robert by saying that life is worth living and informs him that Frank's band is performing at the Starlight. Suzie departs, hoping that she made a difference in Robert's life.Redmont quickly befriends the members of the band, helping advertise for them by placing fliers around town. One night a few weeks after Redmont's reappearance, he finds Frank upset at the fact that the other members of the band are not willing to meet their rigorous rehearsal obligations. Suzie also notices Frank's increasing irritability when she inquires if he knew someone who might match the description of Robert Grayson and he dismisses her to continue rehearsing.Back in 2020, Frank finds Suzie's camcorder lying around his house and watches the footage she captured of her encounter with Grayson. Coupled with the fact that a news notification informs him of recent disappearances across town, Frank realizes something sinister is taking place across town that had been suppressing his memories until now.Frank calls Mike and Jack who rendezvous at the Barrens' home. They catch up, as they evidently have not seen each other in thirty years. The more they talk, the quicker the band realizes that something is suppressing all of their memories. Frank informs them that his memory not only has been hazy too but that he believes it has to do with the night they performed at the Starlight Club in early 1991.In 1991, Suzie comes back to town to attend the band's performance at the Starlight. After their show, Suzie plans to congratulate the band in their dressing room, but she overhears them having a heated argument during which Frank blames Mike's laziness and Jack's arrogance for ruining the show. Once Jack and Mike storm out, upset, Suzie approaches Frank to reason with him but he ultimately blames her for the band's failure just as much as the others. In a fit of rage, Frank yells at Suzie, resulting in her fleeing. Once she departs, however, the scene dissolves, revealing it was a false memory that never transpired that a sinister power has placed in the band member's memories. In reality, the band's performance actually went quite well and Suzie never arrived, causing Frank to be concerned.Suzie suddenly appears in a dream-like realm, devoid of any other presence, still believing the band's argument to have actually taken place. In the dream-realm, Suzie is visited by apparitions of the future versions of the band, who blame her for ruining their lives.Mike runs into Miller and Tucker outside the Starlight, fighting with Redmont. When Mike attempts to intervene, he discovers the bullies are super-humanly strong and have somehow been brainwashed. He even witnesses Tucker disappear with Redmont right as Miller attempts to kill him for intervening and for stealing a knife from the woods which possesses supernatural properties.Jack and Frank witness Miller pursuing Mike and they chase them both to the Grey House where Miller attempts to kill Mike with the stolen knife. Even though Jack and Frank intervene, Miller's newfound strength and a magically materializing Tucker threaten to overpower them.Back in the dream world, Redmont appears before Suzie with his memories restored and informs her that everything she has seen has been an apparition from the sinister force that abducted her. Redmont and Suzie vanish from the dream world and reappear at the Grey House. They arrive just in time for Redmont to use telekinetic powers he has manifested from his time in the dream world to save the band. Redmont incapacitate Tucker and Miller.The sinister presence causes the incapacitated bullies to vanish and the heroes detect its presence inside the Grey House. They enter the house to confront whatever has been behind the attacks but as soon as they step inside, Red begins to writhe in pain from a psychic attack. Grayson appears, revealing that the sinister force is called "the Void" a supernatural entity that requires a host to operate just like a parasite and that he is that host. Despite his youthful appearance, Grayson reveals he has been the host for the Void for an entire generation. It has kept him young but it has deprived him of his humanity and it now requires another pure-heart host, namely Suzie Barrens, to survive. The band attempts to protect Suzie but are no match for the Void's powers. Jack and Mike are rendered unconscious and Frank is on the brink of death from a psychic attack. Redmont fights through the pain at Suzie's insistence to defeat Grayson with his own powers.When the band reawakens from blacking out a short time later, they find that Redmont and Grayson have vanished just like the bullies and that Frank has been paralyzed. Jack and Mike help Frank over to Suzie who they find bleeding out on the floor with only moments left to live. She informs the band that while she was inside the Void's dream world, she sensed that it would wipe their memories once they left the house, just like with Redmont. She also believes the Void will attempt to return in another generation. She makes them promise to return and defeat the Void once and for all as it has only disappeared temporarily. As she dies and her body fades away, she encourages them to take on the new name of "Magnum Opus", Latin for "great work".In 2020, the band returns with their memories restored. Frank comments to the unseen Void that they will succeed since they have remembered the "light", Redmont's power which defeated Grayson in 1991. Frank realizes that the Void wanted to control Redmont and Suzie because they were noble individuals but that the Void will never possess that nobility because that was what defined Suzie and Redmont. They prepare to enter battle against their unseen foe.Roll credits.In an after-credits scene, the journal from the beginning of the film lies on the floor of the Grey House, unopened.