Deep in the woods, Ash spies a Treecko. He's wanted to catch a Treecko since he first saw one at Professor Birch's laboratory. He follows the Treecko to an enormous tree that seems to be dying. There, Ash's Treecko has an argument with all of the other Treecko. It seems that Ash's Treecko is very attached to the tree and wants to stay with it, while the rest of the clan wants to move on to a new tree. Ash watches as the lone Treecko struggles to save the tree. He and Pikachu feel badly for the Treecko and try to help. In the end, however, the tree dies and falls. Now that its home is gone, Treecko is ready to make a new home with Ash. He and Pikachu battle, and Ash catches his Treecko!
The Who's that Pokémon? of this episode is Girafarig.