To earn the money, Paddington takes on odd jobs: cleaning windows, cutting hair (disastrously), and becoming a neighborhood "whisperer." Meanwhile, a charismatic but fading actor, Phoenix Buchanan (Hugh Grant), lives next door to the Browns. Phoenix is a narcissist who performs one-man shows of his old dog-food commercials. He discovers the pop-up book contains clues to a hidden treasure—a large fortune supposedly left by the explorer who gave the book to Aunt Lucy.
The final clue leads to a decommissioned steam locomotive at a heritage railway. The treasure is hidden in the engine’s tender. Phoenix arrives disguised as a train conductor and retrieves the treasure—a chest of gold coins and jewels. The Browns confront him, but Phoenix locks them in a baggage car and sets the train in motion.
The treasure is returned to the museum, but the pop-up book is ruined during the chase. Heartbroken, Paddington thinks he has nothing for Aunt Lucy. However, the Browns, the prison inmates, and the entire neighborhood have secretly pooled their resources. They present Paddington with a brand new, one-of-a-kind pop-up book—this time featuring Paddington’s own adventures in London, with Aunt Lucy as the final pop-up figure.