It starts with a baseball thrown into a window. The owner scolded Nobita even though Gian does it but he forces Nobita to admit. He scolded to Doraemon why don't the owner change the glass to metal? Doraemon give Nobita the Materials Quality Changing Machine and he change many things to another material. Gian took it but requested Doraemon to repair it after accidentally turning his house to paper house.