POKEMON MYSTERY DUNGEON: love story Of lucario and delphfox

This story is about lucario and delphfox. In 7 year later after finishing up his mission lucario was about to go to library to find a book called "meganiumheart's" when Lucario went to the front desk he saw delphfox work on some paper after delphfox was done she gave Lucario a death stare. Something happened in the last 7 years between Lucario and delphfox but what. Read it till you find out.