The Staircase will explore the case of Michael Peterson.

Game of Thrones star Sophie Turner is set to return to our screens in a brand new true crime series from HBO. The Staircase will see Sophie play Margaret Ratliff, the adopted daughter of novelist Michael Peterson, who was accused of murdering his second wife Kathleen in 2001. Joining the Game of Thrones star is Colin Firth, who will take on the lead role. Toni Colette, meanwhile, will play his wife. This eight-part series will examine the circumstances and reports surrounding Kathleen's death. Peterson was convicted of murder in 2003, but this charge was later reduced to voluntary manslaughter after a judge ruled that a critical prosecution witness gave a misleading testimony. He was released from prison in 2017, and subsequently wrote his own account of the case, in an independently published memoir, Behind the Staircase. If the name The Staircase rings a bell, that's because it's based on the 2004 documentary series of the same name. The miniseries was later extended with new episodes from Netflix in 2018. Colin Firth and Toni Collette joined the cast of the show last month, and Sophie Turner is the latest addition. Originally, Harrison Ford had been cast to play Peterson but he was eventually replaced by Firth. This will be Firth's first TV lead since his 1995 performance in Pride and Prejudice. Speaking ahead of filming, the show's director, Antonio Campos said: "This is a project I have been working on in one way or another since 2008. "It's been a long and winding road, but well worth the wait to be able to find partners like HBO Max, Annapurna, co-showrunner Maggie Cohn and the incredible Colin Firth to dramatize such a complex true-life story.” A release date for the series is not yet known, but we'll be sure to keep you updated.