どこでもドアで北極に来たのび太は、ロボットの部品を発見。それを持ち帰り、誰もいない鏡の中の世界でロボットを完成させる。
だが、実はこのロボットには恐ろしいミサイルがついていた…。
さらに、現実の世界で、ロボットの持ち主だという謎の少女リルルに鏡面世界に入るための道具を貸してしまったのび太。だが、しばらくして鏡の世界をのぞいてみると、そこには地球を攻撃するための基地が作られていて…！？
The story begins with Nobita and Shizuka sitting on the pipes in the yard they hang out at while Suneo showed off his robot. Nobita grew jealous and asked Doraemon to build him a giant robot. Coincidently, robot parts began to fall from the sky. Then Nobita and Doraemon began to assemble the robot. As soon as they finished, Nobita, Doraemon, and Shizuka realized that the robot (Zanda Clause) was a war machine in an incident. After that Nobita met a girl name Riruru, she told Nobita that the robot was her's. Nobita gave her the robot and the entrance to mirror world. Doraemon and Nobita followed Riruru and recognized that she was a spy from Metropolis and built a base to welcome the army.
