A New Book Series
It's public now: I'm working on a new book series. It's called Osasto K (Department K), and the first part will be published in June 2026. I've already been writing the second book alongside the first. It's scheduled to come out later the same year.
The Osasto K books will be published by WSOY. Huge thanks to their amazing team for welcoming me so warmly into the house! And an equally big thank-you to the people at Otava for the great collaboration on my first three novels.
Many readers have asked if I'll return to the world of Leo Koski, but there are no new Koski books planned for the time being. Leo's fate was sealed by the very thing that made him a hero in the first place. A billionaire and former Prime Minister only works as a central character in stories set at the very peak of power and money. If I ever get a brilliant idea that demands such a protagonist, Leo Koski will return to the path of danger.
For now, though, Leo gets to rest, because Osasto K will take all my time for the coming years. I won't say much about the main characters of the new series yet—only that they're not high-level politicians. I can tell you this: this time, the entire idea for the series started with a single character that came to mind—not with the plot, as has usually been the case for me.
Below is the official press release from WSOY, published today:
WSOY to publish Tuomas Niskakangas' new thriller series – Osasto K to launch in June 2026
Tuomas Niskakangas, one of Finland's leading voices in thriller fiction, is launching a brand-new series titled Osasto K—a story about power operating without oversight, and people who can no longer look the other way.
The series combines the intensity of a political thriller, the intricacy of high-level power plays, and the suspense of a criminal investigation with sharp psychological character work. WSOY will publish the first book in June 2026, with the second installment to follow already in the same fall.
"I admire Tuomas Niskakangas' ability to explore the urgent issues of our time from both national and international perspectives. We are thrilled to begin a multi-year partnership with him. Osasto K will undoubtedly capture readers and hold them in its grip," says Anna-Riikka Carlson, Publisher of Finnish Fiction at WSOY.
"Not since my debut novel have I felt such burning passion to tell a story to readers. That's why I was overjoyed by the enthusiasm WSOY showed in joining me for this project. I'm thrilled to bring this story to readers and listeners together with WSOY," says author Tuomas Niskakangas.
Niskakangas is a writer and journalist whose passion lies in thrilling stories and chilling visions of the threats facing our world. Osasto K blends political intrigue, networked power games, and criminal investigation with deep psychological portraits.
"I love big mysteries from the heights of power. My earlier books have featured power-hungry villains whose actions nearly throw the world off its axis. In Osasto K, the spotlight shifts to those whose lives those villains seek to destroy," Niskakangas says of his new series.