Psychic Elise Rainier (Lin Shaye) has started working as a professional paranormal investigator, with the help of her assistants Tucker (Angus Sampson) and Specs (Leigh Whannell). When he receives a call for help from a man in New Mexico, she feels compelled to assist – the site of his apparent haunting is Elise’s childhood home.

The Last Key marks the fourth instalment of the Insidious horror franchise, and acts as a direct sequel to 2015’s Insidious Chapter 3. That film was a prequel set before 2010’s original Insidious. All this leads to an increasingly unique set-up for a multi-film franchise, and with The Last Key neatly filling a narrative gap between the events of the third film and the events of the first. It also features flashbacks and a prologue of its own, filling in details of Elise’s childhood and backstory. By the end of The Last Key, the Insidious saga feels pretty comprehensively filled out; there is nowhere to go from here but forwards.

It is a good film for Lin Shaye, who benefits from having the narrative heavily wrapped around her character for what is essentially the very first time. She is gifted with more interesting and varied material, and actually does an excellent job with the additional focus and screen time. It also provides the character of Elise with a family – not just in her childhood but via the introduction of a resentful brother (the always watchable Bruce Davison) and a pair of nieces (Spencer Locke and Caitin Gerard).

While Elise benefits from more material, it is sadly a different case for Tucker and Specs. The characters have always acted as a fairly haphazard comedic double act, and here they are presented in a particularly retrograde manner. When introduced to their business partner’s nieces their behaviour is immediately taken over by leering sexual interest, and deeply unwelcome romantic advances upon the women. It is unenjoyable to watch and damages their characters, and seems particularly odd because they never behaved in such unlikeable ways before.

The film takes its sweet time in getting started, with an opening hour that tests the viewer’s patience and suffers from a distinct lack of suspense. When matters shift suddenly – and potently – it is a different matter, and unfortunately a much stronger midpoint and climax may be missed by audiences that have tuned out or stopped watching. At its best, The Last Key feels as good as the strongest moments of the original two films. Overall, there is simply too much chaff burying the wheat, so to speak. While the film is written by Leigh Whannell – making the bad characterisation of Tuckers and Specs all the more bizarre – it directed by Adam Robitel (The Taking of Deborah Logan). His work is reasonably effective, although not as inventive or distinct as James Wan’s work in the first two instalments.

The film ends where 2010’s Insidious begins – and in quite a creative and effective manner – which leaves the series at a significant crossroads. The segue into prequels during the last two films has seemed an odd choice. With events brought up to the original starting point, the next film – 2023’s The Red Door – is left to finally provide a sequel to chapters 1 and 2. Hopefully it proves to be a valuable shake-up of the premise.