On page 88, Lyddie receives a letter from her mother. The letter is very depressing. It asks for money, tells Lyddie that the other children are not doing so well, and says that Lyddie's baby sister, Agnes, is dead.
After finishing the letter, Lyddie tries to remember what Agnes looked like.
She strained, squenching her eyes tight to get a picture of her sister, now gone forever. She was a baby. She couldn't have been more than four the winter of the bear, but that was now nearly two years past. She would have changed.
Lyddie's thoughts of Agnes take Lyddie back to when a bear invaded their house, and Lyddie fended it off. That was just about the last time that Lyddie saw her mother and Agnes, because it was after the bear attack that Lyddie's mother left with everybody except Lyddie and Charlie. The above quote confirms for readers exactly how long Lyddie has now been on her own. She has been away from her farm and family home for almost two years.