Bert is a little mushroom living on a forest clearing who wakes up one morning and finds his beautiful mushroom hat missing. While he is searching for it desperately his neighbor Bertholde is happily talking to a stranger. It is a little spider and Bert is shocked to discover that this spider is wearing his hat! It is too far away to reach, because Bert is a mushroom and rooted to his spot. Will he find a way to get his hat back?