What is insidious the red door about?

Insidious: The Red Door is a 2023 American supernatural horror film that serves as the fifth installment in the Insidious franchise and a direct sequel to Insidious: Chapter 2 (2013). The film was directed by Patrick Wilson in his directorial debut, with a screenplay by Scott Teems based on a story by Leigh Whannell and Teems. Produced by Screen Gems and Blumhouse in association with Stage 6, the film features James Wan as a producer alongside Jason Blum through his Blumhouse Productions banner. The plot continues the story of investigative journalist Jules Lambert (Ty Simpkins) and his mother Janet (Rose Byrne), who are pulled into a dark supernatural world involving the demon realm known as The Further. Wilson, Simpkins, Byrne, Andrew Astor, Steve Coulter, Joseph Bishara, Whannell, Angus Sampson, and Lin Shaye reprise their roles from previous films, while Sinclair Daniel and Hiam Abbass join the cast in new roles. After the release of Insidious: The Last Key in 2018, Blumhouse opted for possibilities to produce future films in the franchise, leading to this sequel that returns to the events of Chapter 2.