Insidious, a small-budget horror film starring Patrick Wilson and Rose Byrne, was a surprise success in 2011, with both critics and audiences. It kicked off a prolific franchise that continues in this year's Insidious: The Last Key. The new film will explore the backstory of everyone's favorite demonologist, Elise Rainier, as she goes back to her childhood home to battle a demon she unwittingly loosed on the world as a child.

The Insidious saga is comprised of four installments set in two different time periods, so there's an increasingly intricate mythology in place. With The Last Key hitting theaters soon, here's a comprehensive guide to the franchise's storyline so you're all caught up when you experience Elise's next trip into the Further.

Note: Spoilers follow for all films in the series except Insidious: The Last Key.

1. Insidious: Chapter 3

[Credit: Focus Features]
[Credit: Focus Features]

Chronologically speaking, this is the first chapter in the series. The story centers around Quinn Brenner, a teenager who desperately tries to contact her deceased mother through occult means. Her efforts to reach out to the spirit world backfire, and instead of contacting her mother she ends up attracting a malignant presence hellbent on dragging her down into the land of the dead, known as The Further. With no one else to turn to for aid, Quinn's father pays a visit to a psychic named Elise Rainier.

Yet Elise had hung up her demon-hunting hat a year prior and refuses to help the Brenners. She's got her own difficult supernatural history: shortly after her husband's suicide, Rainier tried to contact his spirit to get some form of closure. Just as Quinn experienced, however, Rainier's trip into the Further opened the door for an unsavory character: a sadistic old woman dressed in black, who made it her mission to kill Elise after she severed the woman's link to a young boy named Josh Lambert.

That looming threat forced Elise to retire. Fortunately, she changes her mind after realizing Quinn's grave situation. This is when she meets Tucker and Specs, a duo Quinn's father hired as a last resort in his bid to save Quinn. Aided by the two technicians, the brave psychic enters the Further once again, battles the woman haunting her, and retrieves Quinn's soul. With their case solved, Tucker, Specs and Elise decide to work together as paranormal hunters.

2. Insidious: The Last Key

[Credit: Universal Pictures]
[Credit: Universal Pictures]

The newest chapter in the series picks up right where Chapter 3 left off, as Elise, Tucker and Specs continue their ghost-hunting business. In this installment, Elise receives a call from a man haunted by demons. This isn't just an average case, however. The man being terrorized lives in Elise's old childhood home, and the threat he's facing is a creature she set free when she was just a child.

3. Insidious

[Credit: FilmDistrict]
[Credit: FilmDistrict]

Insidious is the first installment in the franchise, but the third chapter in the overall story. The plot takes place a few years after The Last Key, and it centers around Renai and Josh Lambert, a married couple who move into a new house with their three children, Dalton, Cali and Foster. One night Dalton encounters a dark presence in the attic, and falls down a ladder. The next day, the boy mysteriously falls into a coma.

After three months of unsuccessful treatment, the Lamberts take Dalton back home. Unfortunately for them, they experience attacks from ghostly entities. While they decide to move, the family soon learns the house wasn't the problem. Seeing their predicament, Lorraine, Josh's mother, calls in Elise, who she's known ever since Elise helped free Josh from the aforementioned woman in black, dubbed the "Bride in Black."

Elise, Tucker and Specs visit the Lambert family. The psychic reveals that Dalton has the ability to travel into the spirit realm, just like his father had as a child. The boy's constant trips to the Further alerted evil spirits which crave life, and one of the most powerful demons, the Lipstick-Face Demon, set out to possess him. Elise tells Josh that he needs to go into the land of the dead to get his son back. Josh manages to rescue Dalton, but on their way out of the Further, he encounters the Bride in Black. The father-son duo successfully exit the hellish afterlife they were in, but not everything's done.

Elise notices something off about Josh and takes a picture of him. At that point, she learns that Josh is actually being possessed by the Bride in Black. Before Elise can react, the spirit murders her.

4. Insidious: Chapter 2

[Credit: FilmDistrict]
[Credit: FilmDistrict]

Chapter 2 picks up right after its predecessor. With Josh trapped in the Further, the Bride in Black inhabits his body and takes over his life. She isn't doing a very good job hiding her identity, though. Because of that, Josh's mother, Renai, along with Tucker, Specs, Elise's spirit, and a psychic named Carl, set out to learn the demon's backstory. The group discovers that in life, the Bride was actually a man named Parker Crane, who was tortured by his mother from an early age. As an adult, Crane became a serial killer. Eventually, he ended up in a hospital, where he met a young Josh Lambert.

Shortly after their encounter, Crane committed suicide and began stalking Josh as the Bride in Black. With this information, the paranormal investigators hatch a plan to take out the demon and recover Josh from the Further. Unfortunately, their strategy goes awry and Renai and her children are chased by a possessed Josh. With no other options, Dalton goes back to the Further, and alongside Elise helps his father return to the world of the living.

With the Bride finally banished, Carl helps Josh and his son forget their supernatural ordeal. Sometime after this event, Tucker and Specs –– who are continuing their ghost-hunting practice –– visit the family of a young girl who suffered an accident caused by a supernatural entity. Unbeknownst to them, Elise's spirit goes into the girl's house and tries to talk to her. At that moment, the seasoned psychic spots an evil presence hiding in the shadows right before the screen cuts to black.

And now you're all caught up!

What's Next For The Insidious Timeline?

Given that The Last Key is the second prequel in the Insidious franchise, you may be wondering what we can expect in the future. Will the saga reveal what happened after Chapter 2 or will it continue to explore Elise's frightening cases?

During an interview with We Got This Covered, head franchise writer Leigh Whannell revealed he was interested in exploring more of Elise's adventures prior to helping out the Lambert family:

I'd like to explore the time between this film and the first film. That whole area there where Elise has rediscovered her gift, I think you could have a lot of adventures before she arrives. So I think there is a lot of room there. We've kind of established Lin [Shaye] [...] as kind of this superhero, so that would be kind of interesting to explore in the other films.

Chapter 2 made it clear that Elise had quite a few cases under her belt, so it'll be interesting to see what the talented demonologist encountered prior to meeting her ultimate fate in the first film.

Insidious: The Last Key hits theaters on January 5, 2018.