Sailor moon was fighting a crook that had just broken in and stolen from a candy store with Tuxedo mask near seven at night. Usagi Tsukino's mom was walking by the back side of the store (at the same time as the crook)when she saw some little kids. Quietly, she wished that Her little girl, Usagi and her girl's boy friend, Dairien, could see when Usagi was little.
" I wish that Darien and Usagi could see when Usagi was little because she was so cute when she was little. I just can't believe she has changed so much. If only she loved school as much as when she first started school."
It turned out, there was a time key in the store, and when you wish apon a time key, your wish will be granted.(The time key was buried under the store long ago.) Right after the crook was dealt with, Sailor Moon and Tuxedo Mask all of a sudden "disappeared" or were sucked away into the past. However, there were consequences for someone without magic or knowledge of how to use a time key, and Usagi had to deal with the consequences. In Usagi's case, when she went back in time, she was turned into the body she had when she was seven.