The eccentric Mr. Magorium has announced that he is leaving his toy store to his assistant Molly Mahoney. Unfortunately the store doesn't seem to like the idea.

In the Old City of Quebec, Kay Harper falls in love with a puppet in the window of the Quatre Mains, a toy shop that is never open. She is spending her summer working as an acrobat with the cirque while her husband, Theo, is translating a biography of the pioneering photographer Eadweard Muybridge. Late one night, Kay fears someone is following her home. Surprised to see that the lights of the toy shop are on and the door is open, she takes shelter...

"Things are calm at last in Maple Bluffs. The evil manufacturer SmilesCorp is out of business, Hammie Rex is a new dad to three tiny mutant offspring (Stompy, Chompy, and Hatshepsut), and Sam Gibbs feels that he can resume normal life. But soon enough, things get weird. When Sam visits a toy store to buy Beefer a bar mitzvah gift, one of the toys comes alive and attacks Hammie and the babies! Who could be behind this latest diabolical scheme?"--Provided...