In 1994, the Swedish engineer, entrepreneur and adventurer Malte Stierngranat was buried in a pyramid he had designed himself. The pyramid had been built almost half a century earlier on land he bought close to his home. He also had a personalised coffin made, which he took on his trips, even short ones.

Carol is contacted by the cleaner George in the middle of a cold Swedish winter. Her investigation leads her into Malte Stierngranat’s life and legacy. George is the cleaner and caretaker of Malte Stierngranat’s son, Erik, and his family, who have gone missing.

As Carol thinks she has reached a dead end, the boyfriend of Malte Stierngranat’s granddaughter is found dead in the family’s old barn. Police determine that his body had been in the barn since the family disappeared.