From the radar episode 3: secret documents and the last shot from the cockpit

For almost their entire lives, Marianne and Greet have known virtually nothing about the air disaster in which they lost their father. But all the while, the boxes containing all the research information were within easy reach. Less than 100 kilometers away, but under lock and key by an old treaty. Until the doors opened for a moment. Episode 3: Right through a concrete wall.