Colin is small, even for a mouse. His mother refuses to let him play outside with his brothers and sisters unless he is wrapped in a big fluffy ball of cotton wool. But instead of keeping him safe, the cotton wool attracts the attention of every fierce creature imaginable - little boys, ducks, even foxes! After a day of being flung, pecked and chased, Colin returns home without his cotton wool, but feeling much BIGGER, and ready to tell his mother that he can look after himself.