"The Staircase" is a true crime documentary series that follows the trial of Michael Peterson, a novelist accused of murdering his wife, Kathleen Peterson. The series explores the complexities of the legal system, the evidence presented, and the impact of the case on the Peterson family. The documentary originally aired in 2004 and was later expanded with additional episodes in 2018. It provides an in-depth look at the investigation, courtroom proceedings, and the various theories surrounding Kathleen's death, including the possibility of an accidental fall or foul play.