Stefan and the Spirit of the Woods - Robert Wingfield - Bog

An ecological modern fairytale.
It has been a long winter on the island where Stefan lives but spring has finally come. He and his two friends set out on their bikes to explore the forest and the mysterious hill in the middle.They never get that far.
When one of them carelessly drops a plastic bag, it invokes the anger of the forest spirits. The final result is one that none of the children could have predicted, but changes all their lives forever.