'Slow Horses': Gary Oldman contends with Hugo Weaving in Season 4 trailer

Apple TV+ is teasing Slow Horses Season 4.

The streaming service shared a trailer for the season Tuesday featuring Gary Oldman and Hugo Weaving.

Slow Horses is a spy thriller based on the Slough House book series by Mick Herron. The show follows Jackson Lamb (Oldman), the leader of a dysfunctional team of MI5 rejects known as the "Slow Horses."

Season 4 opens with "a bombing that detonates personal secrets, rocking the already unstable foundations of Slough House," according to a press release.

In the trailer, Lamb (Oldman) and his team must contend with Frank Harkness (Weaving), who appears to have created "an assassination squad."

Kristin Scott Thomas, Jack Lowden, Saskia Reeves, Rosalind Eleazar, Christopher Chung, Aimee-Ffion Edwards, Kadiff Kirwan and Jonathan Pryce also star, with Weaving, Joanna Scanlan, Ruth Bradley, Tom Brooke and James Callis to join the cast.

Slow Horses Season 4 will premiere Sept. 4 on Apple TV+.