It is a megatrend of the future, renowned economists even expect a new industrial revolution through 3D printing. The technology has been around for 30 years, but until recently the devices were prohibitively expensive industrial monstrosities. Today, printers are neither bigger nor more expensive than a PC. They are undergoing the same evolution that computers once did: From large-scale factories to desktops. Products from 3D printers are already part of everyday life. Thousands of Germans have dental crowns in their mouths that come from printers. Senior citizens wear hearing aids whose outer shell is printed. We are on the road with aeroplanes that contain printed components. But this is just the beginning. The 3 Sat science documentary asks: Where everywhere have 3D printers already left their mark? How are they changing our lives? What problems do they bring with them? The first functional weapon has already been printed, its construction plans are available on the internet. And because it is made entirely of plastic, conventional detectors cannot detect it.