Rebecca (better known as Rebel) Blue is not what anyone would consider a joiner, not even a group of misfits to have lunch with. She has blue hair and took up smoking at age 12 because it "bugged the hell out of Aunt Evelyn." Rebel is familiar with detention and when a teacher decides to have them make a bucket list Rebel has no plans to take it very seriously. In this particular detention though Rebel crosses paths with Kennedy Green, and aside from both having a last name that is a color and being in detention that day, they have nothing in common with one another. Kennedy is a perky over achiever who actually relishes putting her bucket list together. However, when Kennedy dies shortly after leaving detention and Rebel is one of the last people to talk to her. Now she can't get Kennedy's voice and bucket list out of her head. Eventually (partially to spite her cousin) Rebel decides to complete Kennedy's bucket list. In working on the bucket list Rebel is forced to take part in a world she's being doing her best to avoid.
While Rebel completing Kennedy's bucket list and beginning to grow as a person and forge real friendships, etc. is a predictable path to take Coriell makes the path bumpy and interesting. Even though this experiment has her working with and trying to help others she is still by no means someone with any desire to conform. Goodbye, Rebel Blue has Rebel opening herself up to people (including a cute boy, who belongs more to Kennedy Green's world than hers - who is really a bit of a flat character at times, but his little sister is hilarious), dealing with the loss of her mother who died years earlier, and trying to do it all on her own terms.