After fighting off a giant mutant spider in a cave in the Forbidden Forest, Steve found a half-buried skull that turned out to be cursed, turning him into an evil monster called Herobrine, with cruel and supernatural powers. Alex finds herself in mortal danger and must find a way to deal with 'Herobrine' before he vents his rage on her and Donkey. But just when all seems lost, something unexpected happens - with terrible consequences for Donkey. Now Alex must destroy the cursed skull if she has any hope of saving her beloved donkey from a fate worse than death.