Translator Ichiro Tadano (Nao Omori) decides not to have a dog. when he was young, he cared for a dog named Saba as if the dog was his younger brother, but the dog was killed in a car accident. His wife Masato (Nanako Matsushima) brings home a Labrador dog named Lucky to their new mansion to raise. Ichiro opposes the idea, but Masato insists they have the dog.
Lucky is a very smart dog. Lucky does not respond, unless people call his name. In the afternoons, Lucky stays with Ichiro after Masato goes out for work. Ichiro begins to open his mind to Lucky and eventually has a warm and strong relationship with Lucky, but then Ichiro gets sick. Because of Ichiro s illness the couple experiences hard times. Lucky is the one to save them.