Stephen Chbosky, author of the beloved YA novel The Perks of Being a Wallflower, has announced his second book, Imaginary Friend. The book, which he’s been working on for nine years, is set to hit shelves Oct. 1 via Grand Central Publishing.

The forthcoming novel will be Chbosky’s first foray into the literary world since he penned his debut The Perks of Being a Wallflower 20 years ago.

“Twenty years ago I published my first novel, The Perks of Being a Wallflower,” Chbosky wrote on Twitter Monday. “I have spent the last nine years working on my second. It’s called Imaginary Friend.”

Dear Friends, Twenty years ago I published my first novel, The Perks of Being a Wallflower. I have spent the last nine years working on my second. It’s called Imaginary Friend. It comes out October 1st. https://t.co/Djm2646G2wpic.twitter.com/4Y7zJkd8ce — Stephen Chbosky (@StephenChbosky) May 20, 2019

The new book will be a horror novel, a clear departure from the classic young adult coming-of-age tale (and its resulting 2012 movie adaptation) that launched Chbosky to stardom. The critically acclaimed The Perks of Being a Wallflower touched the hearts of readers around the world, selling millions of copies before being transformed into a major motion picture starring Emma Watson and Logan Lerman.

But Imaginary Friend is a bit different.

It follows a single mother named Kate, who flees an abusive relationship with her son, Christopher, at her side. Together, they stumble upon the off-the-beaten-path community of Mill Grove, Pa., but as the two settle down, Christopher disappears. When he returns from the woods six days later, he carries a voice in his head that only he can hear, one that gives him a mission: Build a treehouse in the woods by Christmas—or else.

“Do you remember when you were a little kid and you would look up into the clouds?” Chbosky said in a recent statement. “Remember how the clouds would look like the shape of a dog or a tree or a face? Well, what if you were a little 7-year-old kid now? With a single mom. And no money. And what if you couldn’t help but notice that for the last two weeks, you looked up into the clouds, and it was always the same face staring back at you? That is the origin of my story.”

After 20 years, Chbosky fans are clearly excited.

I know my daughter will be thrilled to hear this, she considers Perks of Being a Wallflower her favorite book of all time, she relates to it so well and it helped open a dialogue between us when she was@struggling with personal issues — Janelle Fontaine (@jnelley1980) May 20, 2019

Thank you, Stephen. Charlie helped me get through high school. Looking forward to your next work. — argenis /är-hen-?z/ (@antropologoDACA) May 20, 2019

This is exactly the news I needed today Although Perks of Being a Wallflower may be just words on paper for some, it means far more to me than I could ever express. Cannot wait to read more of your work — vaughan (@vaughantrapp) May 20, 2019

In the time since his debut novel, Chbosky has focused on film and TV work, writing for the CBS nuclear war drama Jericho, 2005’s film adaptation of Rent and last year’s live-action Beauty and the Beast. He also wrote and directed the 2012 movie adaptation of The Perks of Being a Wallflower himself.

Check out the cover of Imaginary Friend below. You can preorder the book here.