SkekSo and urSu try to remember their past so they can maybe use the names of SoSu’s parents for the kids. They seek the help of the leading masters of Haven. However their urSkeks spirit resists to remember his life and this causes some trouble.
We can see Haven as a whole from the air and the mountain of the Heartspring, which keeps the planet alive.
To give some context, SoSu does not want to exists, because he believes his two separate side has a more meaningfull life than he would. He thinks of himself as a failure and shame for his line and thus only reforms reluctantly during the story. He wants to keep this peaceful life of SkekSo and urSu raising the little hatchlings.