Paddington, now happily settled with the Brown family in Windsor Gardens, has become a popular member of the community, spreading joy and marmalade wherever he goes. While searching for the perfect present for his beloved Aunt Lucy's 100th birthday, Paddington spots a unique pop-up book in Mr. Gruber's antique shop, and embarks on a series of odd jobs to buy it. Hilarity and adventure ensues when the book is stolen and Paddington and the Browns must unmask the thief.