It's the summer holidays and the residents of Welford are spending a week in London seeing the sights. On their first day there, everyone goes to Buckingham Palace to watch the changing of the guard. In the crowds of tourists Mandy and James notice a small chocolate brown Labrador puppy, but when they get close it runs off. Walking in Green Park later that day, they spot the puppy again. Mandy is concerned as it doesn't seem to have an owner, but she can't catch it. It turns out that well-known animal writer Laura Dawson has lost three identical Labrador puppies. Mandy hasn't spotted one puppy all over town, she's seen all three of them in different places! A chase in Piccadilly Circus corners all three pups and Mandy and James get a reward for their help. They take the whole party out for a meal in Chinatown before returning to Welford after an eventful London visit.