In season three, a romantic liaison in Istanbul threatens to expose a buried MI5 secret in London. When Jackson Lamb and his team of misfits are dragged into the fight, they find themselves caught in a conspiracy that threatens the future not just of Slough House but of MI5 itself.

A group of fun-loving American girls burst onto the scene in tightly corseted 1870s London, kicking off an Anglo-American culture clash. Sent to secure husbands and status, the buccaneers' hearts are set on much more than that.

After surviving Godzilla's attack on San Francisco, Cate is shaken yet again by a shocking secret. Amid monstrous threats, she embarks on a globetrotting adventure to learn the truth about her family—and the mysterious organization known as Monarch.

Rocketing into the new millennium in the eight years since season three, Happy Valley has rapidly expanded its footprint on Mars by turning former foes into partners. Now 2003, the focus of the space program has turned to the capture and mining of extremely valuable, mineral-rich asteroids that could change the future of both Earth and Mars. But simmering tensions between the residents of the now-sprawling international base threaten to undo everything they are working towards.