Filbert was a slow-witted,and shy squirrel. He also loved the smell and taste of Apple's cordial.
Filbert was first seen with Great-Aunt Kererra. He was shown to be working with her in the kitchen.
Later on, Corr was seen talking to him about his journey to the tower to see Brother Fir.
When the ravens came to Mistmantle to attack, he didn't realize it at first. When he did figure out about the ravens, he went looking for Corr. He got lost and then attacked by The Silver Prince. The Silver Prince needed entertainment, so he plucked Filbert's head and ripped out the fur on his head, ears, and tail. The Silver Prince was enjoying himself so much that he did not see Apple in the burrow. Apple jumped out and dragged him down the burrow. Filbert realized a familiar scent once he got into the burrow. Apple gave him some cordial, saying that he'd feel better after he drank it. Filbert drank some cordial and started to cry. When Apple asked him what was wrong, he said that his mother used to make the same cordial for him. Apple was happy about this since no one else liked her cordial. She then said she brought a lot of it and they both sat down and drank together.
After the ravens left Mistmantle, Filbert and Apple went to see Urchin. Urchin was unconscious after being badly wounded by a raven. Juniper then gave Urchin some of the cordial Apple brought. After Urchin drank some cordial, he opened his eyes a little, but then closed them.
When Urchin woke up, Apple told him that she and Filbert were getting married. Apple asked Urchin if he was okay with it and he thought that it was wonderful.