One of Carl Bark's greatest comics about Donald Duck. Unlike most of the other stories where Donald goes of on a long journey, this one does not feature Scrooge, only Donald and Huey, Dewey and Louie.
The story begins with that discovers an old map while working at a museum. The map shows where the viking Olaf the Blue first arrived in North America and where he hid the Golden Helmet to prove that he had been there.
A man named Azure Blue sees that Donald find the map and quickly sets his lawyer Sharky to work. It turns out that whoever has the Golden Helmet of Olaf the Blue can claim to be his decendant and heir, thereby becoming to ruler of the entire continent.
Azure Blue manages to steal the map, but the manager of the museum helps Donald to reconstruct it. Then the race is afoot. If not Donald or the museum manager finds the Golden Helmet before Azure Blue and his tricky lawyer, all the people of North America will be forced to live under Blue's tyranny.