20年來，一名連續殺人犯每隔三年就殺害一名男孩。警方辦案不力，其中一名受害者的父親決心親自找出帶面具的兇手，即使犧牲自己婚姻和另一個兒子的愛也在所不惜。根據真實故事改編。Claus Jansen experiences the inconceivable: his 12-year old son disappears without trace from his boarding school and is then found murdered. As the police don't seem all that committed to their enquiries, the father sets out to try and find the sex offender and is successful, albeit many years later. The film is based on the true story of Ulrich Jahr, whose son was the first victim of the "man in the mask" in 1992. After murdering three boys and abusing dozens of others, he was caught in 2011. One of the most disturbing cases in recent German criminal history.
