If you leave a door half open, soon you'll hear the whispers spoken. If your window’s left unlatched, you’ll hear him tapping at the glass. If you’re lonely, sad, and blue, the Whisper Man will come for you.

That’s the chilling playground rhyme at the center of The Whisper Man, a new adaptation of Alex North’s best-selling novel of the same name. Starring Oscar winner Robert De Niro, Michelle Monaghan, and Adam Scott, the new film follows an investigation into a serial killer thought to have been imprisoned years ago. But when children start disappearing, the playground rhyme comes back to life — and the retired detective who first arrested the so-called Whisper Man is called back into action. 

A new teaser poster for the thriller spotlights a chilling scene straight from the book, as the Whisper Man reaches through a mail slot to try to entice a child (Acston Luca Porto) into joining him outside. North was thrilled to see the scene on screen.

“It's an inherently frightening idea, the idea that anybody could be reaching out to your child or talking secretly to them,” the author tells Tudum. “It works really, really well in the film. I was pleased it was there.”

You can see the poster and catch a glimpse of De Niro, Monaghan, and Scott in action in the first-look photos below. 

Directed by James Ashcroft (The Rule of Jenny Pen, Coming Home in the Dark) and written by Ben Jacoby (The First Omen) and Chase Palmer (It), The Whisper Man is Netflix’s sixth partnership with the Russo brothers’ company AGBO. 

“AGBO is excited to be embarking on our sixth film with our incredible partners at Netflix,” AGBO chief creative officer Angela Russo-Otstot said. “The Whisper Man is a gripping thriller, but at its core [it] is a poignant and complex story of father and sons. We are grateful to have one of the finest actors of his generation, Robert De Niro, anchoring that story and with the remarkable James Ashcroft directing.”

Read on for more information about The Whisper Man.

What is The Whisper Man about?

Based on the New York Times best-selling novel by North: When his 8-year-old son is abducted, a widowed crime writer looks to his estranged father, a retired former police detective, for help, only to discover a connection with the decades-old case of a convicted serial killer known as “The Whisper Man.”

Who is in the cast of The Whisper Man?

• Robert De Niro (The Irishman, Goodfellas, Raging Bull, Heat, Killers of the Flower Moon, and many, many more)
• Michelle Monaghan (Gone Baby Gone, The White Lotus)
• Adam Scott (Severance, Big Little Lies)
• Hamish Linklater (Midnight Mass, Nickel Boys)
• Owen Teague (It, You Hurt My Feelings)
• Acston Luca Porto (Dora and the Search for Sol Dorado)
• Will Brill (The Eyes of My Mother, Not Fade Away)

When will The Whisper Man be on Netflix?

The Whisper Man will release on August 28. Keep your ear to the ground for more information.