Tommy is an old and ailing Labrador Retriever whose life is transformed when he finds himself young and fit, and able to speak English.

He meets his master Claude, who also feels rejuvenated, and they celebrate by walking and recounting their past adventures.

A leisurely stroll becomes a race against time when Claude realizes that they're revisiting his past on the eve of a family tragedy.

Will they be able to avert the tragedy? Gradually, Tommy notices that his health is failing him again. Was his transformation fleeting?