Ambrose is a young rabbit with a very strong sense of smell - he's as good at tracking as a bloodhound. He lives in a hutch with his three siblings and his parents, and is owned by Jim, who smells very strongly of cat, much to Ambrose's disgust.

Jim's niece Biddy comes to stay and she desperately wants to take Ambrose home to be her pet. She plays with Ambrose every day, training him to track things with his extraordinary nose - which comes in very handy when his little sister Roly escapes the hutch and ends up down a foxhole. But Ambrose's nose really saves the day when a fire breaks out in Jim's cottage and Ambrose is the only one woken by the smell of smoke. Maybe Biddy's wish to take Ambrose home will come true after all...