Mendou invites Ataru Moroboshi, Lum, and their friends to his family estate to watch the filming of an independent movie built around Tarozakura, an ancient cherry tree, with Lum cast in the lead role. When the script calls for the tree to be cut down, the felled trunk dissolves into foam, and Tomobiki starts unraveling around them: a mountain rises out of nowhere, winter descends mid-shoot, and Lum's powers begin slipping away one horn-spark at a time.