One day, the kind-hearted boy Lucas (Jonah Hauer-King) met a lonely puppy in an abandoned building. Although Lucas' mother forbade him to keep a pet, Lucas, who couldn't bear to see the puppy unattended, took the puppy home and named it Bella. In this way, Bella became a new member of Lucas's family. One day, Lucas' mother took Bella to the Veterans Hospital for treatment. Bella not only did not cause her trouble, but also brought happiness to the originally depressed patients in the hospital. Soon, Bella became a popular star in the hospital. An accident forced Lucas to foster Bella in a friend's home. Bella, who did not understand the owner's intention, decided to run away from home and reunite with her owner with her courage and wisdom.