Confused by the complex timeline of the Insidious franchise? Here’s an explanation of The Last Key’s ending, and what it means for the series. At this point, Insidious is one of the biggest properties in the world of horror, but it’s unlikely anyone would have expected that. Released in the early days of the now enormously successful Blumhouse Productions, the original Insidious made nearly $100 million worldwide on a budget of $1.5 million. Sequels Insidious: Chapter 2 and Insidious: Chapter 3 both continued that tradition, earning huge returns on small budgets.

While it remains to be seen how well Insidious: The Last Key will perform overall at the box office, the chances of it not also generating huge profits are almost nonexistent, thanks to its $10 million budget. It’s worth noting that none of the sequels have been critical darlings, including The Last Key. Still, that doesn’t seem to bother fans. Finances and critical sentiments aside though, the actual plot of the Insidious franchise has gotten a bit convoluted, likely due to no one involved foreseeing that the first film would lead to a long-running series.

Insidious: Chapter 2 was a direct sequel to the original, but also introduced time travel elements that led to characters from the present interacting directly with their past selves. While this allowed for some intriguing revelations about the Lambert family’s connection to The Further, it also left Elise Rainier (Lin Shaye) permanently dead. When stars Patrick Wilson and Rose Byrne – as well as director James Wan – chose not to return for Chapter 3, Insidious went the prequel route, turning Elise into the main character and showing how she first met sidekicks Specs (Leigh Whannell) and Tucker (Angus Sampson).

Insidious: The Last Key picks up quickly after Chapter 3, and sends Elise and company off to assist the new owner of her childhood home. This leads to an exploration of Elise’s rather tragic backstory, including an abusive bastard of a father and a mother who ended up murdered by the key-fingered demon that was featured in all of The Last Key’s marketing. It is revealed that Elise ran away from home at the age of 16, leaving behind her younger brother Christian, and inadvertently allowing a young woman to die.

Elise had always seen spirits, so when she sees an unknown woman in her home, she assumes it to be another ghost. It turns out that this woman – Anna – was very much alive, and had been held captive by Elise’s father in a secret basement room. The key-fingered demon had influenced him to commit these horrific acts, and Anna was far from the only victim. Elise naturally feels responsible for this, having been tricked into unleashing the demon into the world as a little girl back in 1953.

Emboldened, Elise, Specs and Tucker set out to save the house’s new resident Ted Garza from the supernatural forces tormenting him. Surprisingly, they eventually needed saving from Garza, who was also being compelled by the key demon to kidnap, torture, and murder women. Garza is dispatched by Specs, but that is far from the end of the nightmare. Elise’s estranged brother and his daughters visit the family home to recover a childhood artifact, only for one of Elise’s nieces to fall prey to the key demon. With her niece’s spirit now being held prisoner in The Further, Elise sets out to find a way to get her back, only to also fall prey to the sinister creature.

With Elise and niece Melissa held captive in The Further by the key demon, Elise’s other niece Imogen journeys into the terrifying realm in search of her lost family members. Elise’s gift was passed down to Imogen, and she’s the only one capable of venturing over to the other side. While the key demon briefly takes both Melissa and Imogen prisoner, Elise is able to summon her mother Audrey by blowing a whistle that Audrey had promised she would always hear no matter where she was.

Together, Elise and Audrey succeed in banishing the key demon, although it’s unclear if the beast is permanently out of commission. Elise, Melissa, and Imogen head back to their bodies in the real world, and Elise shares a heartfelt goodbye with her mom. Realizing the error of his ways, Christian apologizes to Elise for doubting her gift, and they embrace. Elise finally has a family again, including both blood relatives and surrogate sons Specs and Tucker.

Unfortunately for her, the Insidious story comes full circle in the end, with Elise getting the call from Lorraine Lambert asking for her help in rescuing her young grandson Dalton. As fans will recall, the original Insidious film ends with a possessed Josh Lambert (Wilson) strangling Elise to death. Elise may have found peace for the time being, but she’s not long for this world.

With a subtitle like The Last Key, many fans have wondered whether this fourth Insidious installment would be the series’ last hurrah. Based on the way the timeline becomes a closed loop at the end of the film, it would certainly appear that Insidious is done. Fans know where the story goes from here: Elise gets killed, helps rescue the real Josh Lambert from The Further as a ghost, then hangs around to assist Specs and Tucker from the other side.

While a fifth film could certainly be made that focuses on Specs, Tucker, and ghost Elise continuing to battle the supernatural, having Elise be relegated to the spirit world would greatly limit how she could be used as a character going forward. One assumes that had James Wan and series scribe Leigh Whannell known that Elise would eventually take center stage, they wouldn’t have killed her off at the end of the original movie. The same is likely also true regarding Wan and Whannell’s decision to make Saw’s villain terminally ill. For now, it seems likely that Insidious has reached its conclusion, at least until the inevitable reboot.