There and Back Again [Big Four/RotBTD]

The Big Four. Four BFFs from hundreds of years ago. A series of accidental meetings that blossomed into strong friendships. Until one of them moves. And then dies.
The other three are devastated by this news. They decide not to have their planned meeting when they turn 18.
But fate chooses to unite the four once more. They enjoy hours of reminiscing and story-telling, and get glimpses of how life has been good to each of them.

My book follows the story lines of all of the movies almost exactly. I changed RotG to better fit the timeline, though, causing Jack Frost to become a Guardian very soon after dying instead of hundreds of years later.
This is a Big Four story. It is not named after Bilbo's book for any particular reason. It's based off a picture I found on Pinterest that I added to the top of each chapter.
Edited, as of 3/31/16!