When his beloved only daughter goes missing millionaire entrepreneur Walter van Dam calls in a team of experts including free climbers a geologist a parapsychologist even a medium to find her for Anna Lena has disappeared somewhere within a mysterious cave system under the old house the family abandoned years ago But the rescuers are not the only people on her trail and there are dangers in the underground labyrinth that no one could ever have foreseen In a gigantic cavern the team come across a number of strange doors three of them marked with enigmatic symbols Anna Lena must be behind one of them but time is running out and they need to choose quickly Anna Lena is no longer the only person at risk
