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

Aug. 13 (UPI) -- 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+.