When 12-year-old Zan finds a helpless newborn pup abandoned in an alley, he takes matters into his own hands. His parents won't let him have a dog, so, swearing his sister Kibby to secrecy, he hides the pup, whom he names Smoke, in his bedroom and smuggles food for him. Through quick thinking, and despite a few near-disasters, Zan and Kibby keep their parents from discovering their pet until Smoke grows too big to hide.