Usagi was traveling to see her future fiancee in his apartment that she has a spare key with as she unlocked the door and entered through.
"Mamo!" Usagi called with a smile to the black haired young man who then turned around with a sad frown on his face.
Usagi's face dropped. The look on Mamoru's face told her that something really bad was about to happen.
"Usagi..." He began.
'No Usako?' She thought in a slight panic.
"Look, it's not working. The two of us aren't right for each other. I think we should not marry and break off the engagement." Mamoru said.
"Why?" asked Usagi
Saori appeared in the background.
"I want a serious relationship and with a serious girl." said Mamoru
Usagi lowered her head and began to shake Mamoru got a slightly guilty at what he thought was about to happen. He expected Usagi begin to cry and beg. However, what happened next shocked Mamoru to his core.
She slapped him hard that he fell to the floor, threw the heart shaped ring and spare key at him and burned all his photos of them and Chibiusa on the stove before leaving him and Saori.
Mamoru was putting out the fire photos and held his cheek at the slap bruise.
"Well I guess I deserve that." he said to Saori healing him.