When Bronty arrives to the McStuffin's household a mysterious outbreak of the Bronto-boo boos breaks out and infected the toys. After sharing a sandwich with Donny, Bronty comes down with a bad case of Bronto-breath.
Doc tries to fix Millie the Microphone when she can't stop repeating words. When Doc gets sand in her eye, she finds out what's wrong with Will's toy digger, Riggo, when his scoop gets stuck.
Lambie becomes jealous and brokenhearted when a new toy steals the spotlight from her during Valentine's Day. A teddy bear discovers why Donny doesn't want to play with him.
A baby toy possum is lost and Doc frantically searches for the baby toy possum and reunites it with its mother. Doc discovers Alma's stuffed bunny in a box at a yard sale.