Aunt Lucy's (voiced by Imelda Staunton) birthday is coming, and Paddington (voiced by Ben Whishaw) decides to give her a gift that will be unforgettable. In the end, Paddington chose a three-dimensional picture book, but this picture book is a precious treasure that is only available in the world. In order to save money to buy the picture book, Paddington decided to start working. After a series of failures, Paddington finally found a job that suits him-cleaning glass windows. Just when Paddington's deposit was about to reach the target, the picture book was stolen by a thief who appeared at the scene of the crime. At the same time, Paddington was arrested as a suspect and was eventually imprisoned. In prison, Paddington changed the lifeless atmosphere inside the wall with his love and courage. Outside the prison, the Brown family never gave up the opportunity to clear Paddington's grievances.