Wings of Fire: Burning Throne

What would happen if Princesses Blister, Blaze, and Burn all had an younger sister?

Princess Barb has always lived her life separate from her royal family besides her dad, King Char. After he cheated on another dragon, Aloe, and had Barb, he knew Queen Oasis would kill him for having a dragonet so he stole her away when she was very young from her life, and hid her. When her father died from a strange sickness she decides to leave the island she was living on, Aegrotatio, and fly to Pyrrhia to challenge her mother for the throne, but it takes an unexpected turn when she finds out that her mother was killed by a scavenger. Instead she has to face her older sister, Blister. Who will win and how will the Sand Kingdom turn out?