Xiao Mi always likes to carry its prey home. Sometimes it’s a mouse, and sometimes it’s a bird. What’s worse, the bird is dead and could not be saved back. In order to solve this problem, the door needs to be modified so that it could automatically recognize what’s going on. If Xiao Mi was carrying the prey, the door wouldn't open. If Xiao Mi was not carrying any prey, the door would open. This is the intelligent system upgrade of "Xiao Mi’s Special Door". The easy-to-read story helps children understand how to make "Xiao Mi’s Special Door" work and to learn independently.