User blog comment:Sargenttacos115/Natsu and Gajeel age Theory/@comment-108.250.20.180-20131117185004/@comment-108.250.20.180-20131118200723

I'll even take all of this a step further in my guessing. The reason Levy is writing to Lucy is she was sent by Makarov to retrieve Yukino and her two keys. The reason being the Eclipse Gate was really just a copy of the same magic used for Lumens Histoire and they need the 12 keys of the zodiac to unlock it and bring back Natsu and Wendy.