The Mystery of the Lost Shadows - E. U. Kerrin - Bog

Some things don't attract attention until they're suddenly gone. Shadows on hot summer days for example. However, when Nela and Ben tell others of their observation that the shadows in their village all disappear without a trace, nobody really listens to them. The two eleven-year-old children decide to get to the bottom of the mystery of the lost shadows on their own. The solution to the riddle lies on a volcanic island far away from the village. Odd figures live here who dream of world domination and forge a diabolical plan. Through a SIM card and the gimmicks of a hacker, Nela and Ben get on the track of the island and its inhabitants...