Josh, in a selfish effort to "upgrade" Fluffy, sneaks into Principal Kirkpatrick’s office and hacks into the GH mainframe. With a few reckless keystrokes, he’s convinced that he’s accomplished his goal… Fluffy is more intelligent, more independent, and is able to complete more tasks for Josh! What Josh doesn’t realize is that he’s also downloaded a harmful living computer virus, Rex-3, into his ultrapet!