INSIDIOUS: The Red Door*CUT TO THE CHASE*
NOTE: This spoiler was submitted by Jeremy
The film opens with the ending of the second film where Josh (Patrick Wilson) and Dalton Lambert (Ty Simpkins) are getting their memories of The Further erased. Jump to about a decade later, where Josh and Renai (Rose Byrne) are divorced, but she brings Dalton, Foster (Andrew Astor) and Kali (Juliana Davies) to the funeral for Josh’s mother Lorraine. Renai tells Josh that he ought to drive Dalton to college the following week, even though their relationship has since become strained after the divorce. Josh then notices a man nearby and approaches him. He says his name is Carl (Steve Coulter), and that he used to know Lorraine.
Josh goes to his car and hesitantly texts Dalton to see if he is cool with the idea of Josh driving him to college. Behind Josh’s car, a blurry figure can be seen walking toward it. After Dalton texts Josh yes, he puts his phone away, and the figure seems to disappear.
Josh drives Dalton to his liberal arts school, where he meets his roommate Chris Winslow (Sinclair Daniel), though he feels there has been a mix-up due to him believing she would be male because of her name. Dalton puts up his drawings and artwork, which include his siblings and mother, but not Josh. Dalton expresses his resentment of Josh, while he calls his son an “ungrateful shit”. After Josh leaves, both of them quietly tear up to themselves.
Dalton begins his class with Professor Armagan (Hiam Abbass), who proves to be harsh and critical when she tells one student to tear up his drawing for seeming too simplistic. When the student refuses, Armagan dismisses him from her class. Per her words, Dalton starts to tear up the drawing he made of Lorraine, even though Armagan says it is beautiful, but she admires his initiative. She then instructs the rest of the class to dig deep into their memories for their next drawing. This triggers Dalton’s memories of The Further, and he uses charcoal to draw a door before a demon hand pushes against his, causing him to bleed on the door. This also appears to awaken something in Josh.
Chris tries to make Dalton more comfortable by getting to know each other. Dalton says he has no memory of when he was ten years old and that he has been afraid of the dark ever since, prompting him to sleep with a bright night light.
Josh goes to the doctor for an MRI scan. While in there, he appears to lose consciousness as the lights go out. Josh starts calling for help until he sees what appears to be a demon in a hospital gown crawling toward him. Josh freaks out until the doctor gets him out and says that he was asleep for 15 minutes and that the scan went well.
Dalton hangs out with Chris as they go to a frat party. They sneak into the room of one of the frat boys, Nick The Dick (Peter Dager), where Dalton ends up in The Further and encounters the spirit of a young frat pledge that died during a hazing incident. He is vomiting into Nick’s toilet and begs Dalton to close the door. Dalton hides under Nick’s bed when he comes in for a condom, and the dead boy reappears and vomits on Dalton before Chris comes to find him. Before Nick comes in, Chris kisses Dalton to make it look like they were just messing around. Nick then makes a crude joke about Chris, leading her to kick him in the balls before she and Dalton flee.
At night, Dalton astral-projects into The Further after going to sleep. He goes to Chris’s new room and uses her keyboard, which wakes her up and alerts her to his presence. She goes back to Dalton’s room, where he tries to explain the visions he has been seeing. Chris later digs into the astral-projecting phenomenon and finds a video from Tucker and Specs (Angus Sampson and Leigh Whannell) explaining it, along with a video of Elise Rainer (Lin Shaye), who Dalton vaguely remembers.
Josh is in his home trying to do an exercise where he hangs up pictures of his loved ones to try and remember them since his memory is feeling fuzzy. Outside, the same figure that stalked him at the cemetery starts walking closer to the window before it crashes through and attacks Josh. After all the commotion, Josh finds a box labeled “Ben Burton”. Josh looks into Ben’s case, as he was a mental patient who committed suicide. The box also contains pictures of Lorraine, which makes Josh realize Ben is his long-lost father that he never knew and always blamed for why he was so screwed up. A note on the back of one of the pictures says “This ends with me”, indicating that Ben thought killing himself would stop the rest of his family from entering The Further.
Chris joins Dalton as they sneak back to Nick’s room for astral projection since Dalton wants to find the dead pledge’s spirit and communicate with him. While there, a more demonic entity attacks Dalton while he is in The Further, and Chris is also attacked in the real world. Nick finds her unconscious but manages to revive her. After she is taken to the infirmary, Chris tells Dalton she can no longer help him.
Josh goes to Renai’s house to speak to her about what he learned about his father. Through their conversation, we learn why they got divorced – Josh, possessed by one of the demons in The Further, chased Renai and the kids with a hammer, which is why Dalton drew the event with Josh looking monstrous. Josh says he needs to go back into The Further once more to put an end to things.
Dalton is also in The Further, reliving the memory of Josh trying to attack his family. Meanwhile, one of the demons is possession Dalton’s body in the real world to attack Chris again. Josh and Dalton manage to find each other and try to run from none other than Lipstick-Face (Joseph Bishara). Dalton is able to get out, but Josh stays behind, thinking it’s up to him to end the terror. He ends up at the red door that Dalton drew, while Lipstick-Face is trying to break through. In his room, Dalton paints over the door, which causes it to disappear and traps Lipstick-Face behind it. Josh then sees a vision of Ben smiling at him, and Josh appears to finally forgive him for leaving him. Josh wakes up to find Renai and Foster relieved that he is okay. Dalton and Chris also stay with each other when everything is done.
Later on, Josh and Renai appear to be in the process of reconciling so he may potentially move back in with her. Before he leaves, he sees a vision of Elise talking to him, saying that he and Dalton have bright futures ahead of them.
Josh goes back to Dalton’s room, where he finds that Dalton has added a painting of the time Josh carried him out of The Further. The two then share a long-awaited hug.
Nearly a decade after their experience in The Further, Josh Lambert has separated from his family after a demon possessed him to chase after them with a hammer. He and Renai are divorced, and Dalton resents him as he heads off to college. Soon, both Josh and Dalton end up back in The Further when their memories are triggered.
Josh learns that the experience goes back to his long-lost father Ben Burton, who was a mental patient that committed suicide because he believed it would stop his family from entering The Further. After a series of hauntings, Josh and Dalton have to re-enter The Further and confront their traumas before the demons can get them. While Josh attempts to stay behind, Dalton finds a way to save him and keep the Lipstick-Face Demon away. Josh also sees Ben's spirit and appears to forgive him.
Josh and Renai appear to be in the process of reconciling, and he repairs his relationship with Dalton.