Doraemon: Nobita and the Platoon of Iron Men

Synopsis:

Following an argument, Nobita follows Doraemon to the North Pole where he finds a strange ball that causes pieces of a giant robot to fall from the sky. After the pair builds the robot in the uninhabited Mirror World, Shizuka accidentally destroys a building with its weapons, and they decide it's best to abandon the robot and keep it a secret. The following day a mysterious red-haired girl named Lilulu begins to enquire about the robot, but after swearing Nobita to secrecy and borrowing the portal to the Mirror World she disappears. A few nights later Nobita follows a strange light and finds the portal to the Mirror World, though when he and Doraemon enter, they discover that Lilulu is building an entire army of robots! As the only ones to know of her plan, it is now up to Nobita, Doraemon and the gang to stop the Robot Empire's plan to invade Earth and enslave humanity.