In may 2008 the Dane Peter Madsen launched the world's biggest civil-built submarine, the 18m long 'Nautilus', in Copenhagen Harbor. Would it float, sink or roll over? All the friends were gathered, they had been helping him for the last 2½ years, shape the giant ion tubes and turn them into a submarine that is able to cross the Atlantic Sea and go down to 200 meters depth. Madsen, who isn't educated, only from what he has found on the Internet, has earlier built two smaller submarines that are still sailing, both over and under the water. This documentary follows the work and spirit of Peter Madsen, from the first to the last submarine, and a little thereafter.