This is the autobiographical account of Mohamedou Ould Slahi who was working as an electrical engineer in Mauritania when one day, two intelligence agents knocked on his door and instructed him to drive with them back to their agency. It was the last time Slahi would see his mother alive.
Moment by moment, Slahi paints a picture of what happened to him. He is arrested by his government and extradited to the custody of the US government. They take him to a black site in Jordan. While there, the US government tortures Slahi for eight months, often torturing him in horrifying, extreme ways. He is flown to Bagram Air Base in Afghanistan, wearing only a diaper, a blindfold, and shackles. He endures two more weeks of torture. Slahi's torture included extreme sensory overload, isolation, and brutal physical violence.
This is when we learn the true nature of the book. Slahi wrote this book from his isolation cell in Guantanamo Bay where he was kept as a prisoner of the US government without ever having official charges filed against him, without due process or legal proceedings. In real life, his imprisonment lasted for 14 years without charges. He was considered to be a member of Al Qa'eda following the 9/11 terrorist attacks.
The story ends without Slahi's freedom being granted, although he was shortly freed thereafter. The story has been seriously redacted by the US government, so the story is often obscured by thick black bands over the top of his words.