The Power Coders are headed to the first-ever Youth App Fest. They hope to win money for new computers with their app idea, a chat bot based on Tommy's dog, Jack. One of the coders, Peter, has been acting distant lately. He claims to be too sick to go. The team is crushed. However, he says they can contact him on a new messaging app. The Power Coders go to App Fest and realize that even though chatting with Peter on the app is fun, they need him there to win. Soon, it's clear something is up with Peter, if that's really who they've been talking to.

This is a book about collaboration, artificial intelligence, friendship, and a major mystery.