In the second half of the 1930 s, there was a village of Greenbridge at the foot of a mine in Yorkshire, northern England. John's father is a mine manager and his mother is a nurse. He helps his parents. They work hard together and spend every day with his classmates Colin and Sandy. One day, John saw a lost puppy near the village. He named it "Lacey" and took it home.

Interested in everything, Lacey, who runs back and forth in the village, is crazy about John. Lacey is just a puppy and likes to depend on her mother's age. Under the same starry sky, John and Lacey are close together, and gradually grow into a well-known dog worthy of the name as the best partner of teenagers. But it didn't take long for the coal mine pit to suddenly run out of coal. Lacey and John were forced to separate for unexpected reasons (Lacey was sold). Since Lacey escaped, she started a hard journey of 1600 km to John's residence.