Violet Mackerel believes that wherever you leave something small, a tiny part of you gets to stay too—like how the little piece of green sea glass under the mattress at the beach house means that a little piece of Violet gets to stay on summer holiday. Violet’s theory is put to the test when Mama and Vincent announce some very special news: They are going to get married. And they are all going to move. Violet is excited for the wedding, but Dylan is angry about the move. Normally, it is nice to be inside with your family when there is a big noisy storm outside and there is pumpkin soup for dinner and something on TV about penguins. But it is hard to enjoy it when your brother is outside in the garden in a leaky tent. When Dylan won’t budge, the wedding preparations feel a bit sad. But just in time, Violet thinks of the perfect way to help Dylan feel better about moving. And her Theory of Leaving Small Things Behind is going to come in handy!