E1 - The Great Lakes

Aired: January 18, 2011

Holger Nilsson meets the temperamental engineer Mortensen. Together they set out on a raging treasure hunt through Sweden to find the seven keys to Mary Diana Graaf's mythical laboratory.

E2 - The Great Plains

Aired: January 25, 2011

To solve the riddle, they hike across the Varaslätten and climb one of the country's highest silos. From the steamboat they see the fields of Västergötland. They fly over Skåne, wander through beech forests and over miles of white beaches.

E3 - The Deep Forests

Aired: February 01, 2011

To solve the riddle, they ride a raft on Sweden's largest river and cable car over waterfalls. From Värmland, they travel by dog sled through Norrlands and endless pine heaths where the taiga is preserved and the great forest is untouched.

E4 - The Long Coast

Aired: February 08, 2011

To solve the riddle, they follow the Norrland coast. They drive through the breathtaking landscape of the High Coast, become shipwrecked on the island of Högbonden and climb high up to Slåttdalsskrevan.

E5 - The Big Islands

Aired: February 15, 2011

To solve the riddle we follow Holger and Mortensen as they wander through the great Alvaret on Öland and Visby on Gotland, they wander among narrow alleys and see ruins from the Middle Ages.

E6 - The Tall Mountains

Aired: February 22, 2011

To solve the riddle, Holger and Mortensen go to the mountains in Dalarna, where Sweden's highest waterfall, Njupeskär, is located. They also visit the mine in Kiruna and hike the Kungsleden down towards Sarek and Rapadalen.

E7 - The Thousand Islands

Aired: March 01, 2011

To solve the riddle Holger and Mortensen kayak through the Stockholm archipelago. They sail with an old pilot boat and visit Sweden's westernmost islands, the Väder Islands.

E8 - The Big Cities

Aired: March 08, 2011

In the final episode, Holger and Mortensen visit Sweden's three largest cities and their most famous buildings and places in order to finally solve the riddle.