Callie was presumably abandoned by her previous owners. She was left in the streets. She had a leg that was cut.
Callie was first seen in the streets spotted by Mia. Later, Mia and her family rescued Callie and fostered her until they could find a home for her. She was taken to the vet for treatments about her cut leg. At the end of the book, she was adopted by Mr. Ling, a pet store owner.
Callie was mentioned in this book by Mia who made a sculpture of her.
Callie is a friendly, caring, loving, and affectionate cat. She loves people and was lonely due to being abandoned. She loves Mr. Ling and was happy to be adopted by him.