There are many settings in the story because the protagonist is constantly changing locations, but one important setting is when "A" took Rhiannon to the ocean.
"A" the protagonist wakes up in a different body everyday. He one day wakes up in the body of Justin. Justin has a girlfriend named Rhiannon which "A" falls in love with her after hanging out with her for a day
The initial incident in the story was when A tells Rhiannon his biggest secret. Of course she doesn't believe him but soon she starts to realize what A said is true and she comes to terms that she wants to be with him no matter what it takes.