Fourteen-year-old Finna and her twin brother Erik embark on an adventure with their best friend, Kalli and an alien creature that only Finn can see. What started as an exploration of a glacier in Iceland ends up taking them to places they could never have imagined and dangers that they never expected. Using clues from hidden papers written with a secret code, they follow the trail from the Sn fell Mountain to a cavern under the Icelandic glacier and...