William, 21, shot two classmates at his high school in the USA. David, 18, murdered nine people at a shopping mall in Munich. Paul, 15, wanted to blow up his school in Germany. This documentary profiles three teenagers with murderous fantasies. But the film also seeks to understand why so many horrific attacks around the world are the work of adolescents - and how their dangerous fantasies take hold in the first place. Hundreds of games are available for download on the gaming and chat platforms Steam and Discord. Up to 50 million people play there, every day. They also communicate with one another, in chats. Often, their messages are harmless. But in some groups, players radicalize one another, often making use of hatred directed towards foreigners and Jews. And, the players often share a fascination with violence. The 18-year-old who murdered nine people at a Munich shopping center was among those active on one of these gaming platforms. How do young people get caught up in this kind of spiral of violence? Filmmakers Alexander Spöri and Luca Zug are both young - just 20 years-old. They have been dealing with this topic since the attack in Munich in 2016. Using an undercover account, they infiltrated this dark world of violence online. There, they came across terror groups in which young people spread radical ideas and planned attacks. They met a young man who was in contact with the Munich bomber in 2016 and was planning to blow up his own school at the time. The documentary aims to raise awareness about this new type of youth radicalization. After all, only by acknowledging the danger can we possibly prevent future attacks.