V.E. Schwab and Cat Clarke are collaborating on a thriller novel.

Harper will publish The Ending Writes Itself, written under the pen name Evelyn Clarke, next year, the press announced in a news release. It says the book “is sure to be the spring's most anticipated novel.”

Schwab is the prolific author of fantasy novels including A Darker Shade of Magic, Vengeful, and The Invisible Life of Addie LaRue. Her most recent book, Bury Our Bones in the Midnight Soil, was published by Tor in June. Cat Clarke has published several novels for children and young adults, including The Lost and the Found, Undone, and The Pants Project.

The Ending Writes Itself, Harper says, will follow a group of six authors who are summoned to a private Scottish island and each given 72 hours to write the conclusion of an unfinished novel by a legendary author who has recently died. “Starting is often the hardest part,” Harper says. “But getting to the end could be murder.”

On its Instagram account, Harper posted the backstory behind Schwab and Clarke’s collaboration, explaining that Schwab “proposed an absurd idea to longtime friend and screenwriter Cat Clarke: that they should write a book together. Victoria had made quite a name for herself, but had sworn she’d never co-write a novel. While Cat, following a tumultuous career as an editor and the author of several YA novels…had fled the publishing industry to work in the even more tumultuous film industry, swearing she’d never return to books. And yet, fate—and an irresistible idea—made liars of them both.”

The Ending Writes Itself is slated for publication on April 7, 2026.

Michael Schaub is a contributing writer.