User blog comment:FairyRaven/Fairy Tail Chapter 336: In Order to Live Today to the Fullest, Review and Commentary/@comment-203.87.139.100-20130621104259/@comment-7405046-20130621112156

What she couldn't solve was the arrival of the 10,000 dragons. In the journal, that was about herself, since F-Rogue belongs to a different timeline and she didn't know about him. Lucy just found a way to use her future self's knowledge about time travel.

About why the journal was there... Chapter 300.