Beginning in 2010, James Wan's horror film franchise centres on the Lambert family who are being terrorised by several terrifying demons that appear in petrifying jump scares throughout.
Ahead of the release of the new film, here is everything you need to know about what has happened in the franchise so far.
Insidious recap: The story so far
The first film opens with the Lambert family, Josh (Patrick Wilson) and Renai (Rose Byrne) and their three kids have moved into a new home with their three children where supernatural things begin to occur.
One day their eldest son Dalton (Ty Simpkins) falls into a coma after a fright and it is can't be explained by doctors, and since they are still haunted by demons Renai concludes that the spirits must be in the house they had moved into.
However, when they move homes the demons follow and so the couple decide to enlist the help of psychic Elise Rainer (Lin Shaye) and her paranormal investigation duo Specs (Leigh Whannell) and Tucker (Angus Sampson).
Elise comes to realise that Dalton is not in a coma, his consciousness has been projected to a place known as The Further where tormented souls of the dead are lost and if he remains that way then the demons haunting him will be able to come back into the world of the living.
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Josh, it turns out, can also use astral projection and so he travels into The Further to find Dalton's spirit, in the hellscape he fights Lipstick-Face Demon and other spirits to get to his son who he is able to bring back to his body.
However, upon their return Elise realises that Josh is not who he once was and has actually been possessed by the Bride in Black, he then kills Elise and Renai realises he has been possessed after a photograph shows the demon has taken over him.
Insidious Chapter 2 (2013)
The horror film's sequel, also directed by Wan, follows directly on from the events of the first movie and sees Josh still possessed by The Bride in Black.
The family move into his mother Loraine's home, who has a previous history with Elise having enlisted her services in the past.
With Elise gone, Specs and Turner take up the mantle and try to find a way to banish The Bride in Black from Josh's body, during their investigation they learn of a man named Parker Crane whose ghost Lorraine had seen before at the hospital she used to work in.
Crane, it is revealed, is a prominent serial killer who was abused by his mother and forced to wear a dress and make-up, leading him to later murder people dressed as the Bride in Black.
Knowing what they are facing, Dalton uses his astral projection ability to travel into The Further and save his father's soul, and there he encounters Josh and Elise. The trio find Crane's mother Michelle and Elise destroys her in The Further allowing Crane to free Josh and return his spirit to his body.
Specs and Tucker begin investigating a new cast of a girl who has mysteriously slipped into a coma, and whose sister Allison (Jenna Ortega) can see ghosts including Elise.
Insidious Chapter 3 (2015)
The third film is actually a prequel, and it follows Elise, Specs and Tucker as they investigate a paranormal event in 2007, three years prior to the original.
In the film, Elise is hired by Quinn (Stefanie Scott) who hopes to contact the spirit of her dead mother, only for the psychic to realise something much darker is lurking around Quinn.
Despite urging Quinn not to try and contact her mother this does not stop the demon, as the teen begins to be terrorised by a man wearing an oxygen mask, The Man Who Can't Breathe.
Quinn begs Elise to help her banish the spirit, and Elise heads into The Further to do so but the demon is so powerful that she only just makes it out for the realm in one piece.
With the help of her mother's spirit, Quinn faces the demon and she kills The Man Who Can't Breathe by removing his mask in The Further.
After, Elise returns home but soon realises that the Lipstick-Faced Demon from the first film is standing behind her.
Insidious: The Last Key (2018)
Set directly before the events of the first film, The Last Key finds Elise coming to the aid of Ted Garza (Kirk Acevedo) who is being haunted by spirits in his home which, it turns out, is Elise's childhood home.
In an earlier flashback, set in 1956, viewers learned how Elise and her brother Christian once saw the spirit of a woman in their bedroom, their father punishes her as a result of her supernatural ability and locks her in the basement where she finds a red door. Behind it is a tormented spirit that possesses Elise and kills her mother, leading Elise to run away from home.
Forced to face the past, Elise brings Specs and Tucker to investigate and they discover the basement's hidden room that she realises was where a woman was held captive by her father. The house's ghost, known as The Key Face, has since been possessing men to make them kidnap and kill young women.
Elise's brother Christian (Bruce Davison) also revisits the home where one of his daughters, Melissa, is attacked by The Key Face and is left in a coma.
In order to defeat the demon, Elise heads into The Further and is held hostage by the demon alongside Melissa's spirit, meaning Christian's other daughter Imogen has to go to the realm as well.
There she tries to fight the creature, and Elise discovers a whistle her mother had given to her and her brother in case they needed her, and when she uses it her mother's spirit is summoned and defeats The Key Face.
As they attempt to return to the land of the living, Elise, Melissa and Imogen open a door to Dalton Lambert accidentally, giving spirits from The Further access to him. They make it back to their bodies and it is then that Elise receives a call from Loraine and Dalton.
Insidious: The Red Door will be released in cinemas on Friday, 7 July.
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Watch the trailer for Insidious: The Red Door