Amber is painting a card for Lisa’s birthday. Before it is dry, Sam folds it in half in his rush to go and visit the Ghostbase. Amber is annoyed, but when she unfolds it she finds the butterfly she was painting is complete. They ask Numberella to explain and she introduces them to the idea of reflective symmetry. At the Ghostbase they find many incomplete pictures and letters. With Numberella's help they use an old mirror to make sense of the items they have found.