John's world is turned upside down when The Great Fire sweeps through London. After meeting his father's friend, Samuel Pepys, John starts a diary, recording everything he sees. When John's precious cat Sammy goes missing, he ventures bravely into the city to find him. Spotting a cat on a boat on the Thames, he rows onto the river alone and finds himself stranded. Luckily, the kindly Mr Pepys, comes to his rescue. By the time he gets home, Sammy is safely curled up on his bed with three new kittens! One of the kittens will be a present for Mr Pepys!