Timmy, Beth and Arthur want to find the missing 200 year old Time Capsule. But it's been moved from it's official burying spot and the only clues to its new whereabouts are in code on a map in their old 3rd grade teacher's freezer. They are in fifth grade now, but they are still friends with their favorite teacher. Their teacher was searching for the Time Capsule and broke her hip. Now, she's in the nursing home, awaiting surgery. Timmy agrees to take care of their teacher's dog until she's well. It's up to Timmy, Beth and Arthur to solve the clues and find the Time Capsule. They also have a science project to complete and they are writing songs for their band. Timmy discovers that his teacher's dog is friends with the homeless man in the woods. And the man who runs the nursing home is a crook, trying to make money from an empty diamond mine. He's also trying to find the Time Capsule. Whoever finds the Time Capsule will win $1000. If Timmy, Beth and Arthur don't find the Capsule, they may learn the town's deepest secret.