Corazon gets himself into big trouble when his mischievous neighbor, teacup pup Oopsie, named after the only word she knows, follows him through the secret fire hydrant portal to Pup Academy where 'no outside dogs are allowed.' Meanwhile, Morgan tries to tech-up the school with not-so productive results.

Charlie and D.O.G take a day off, leaving Morgan in charge of the Academy on his own for the first time. Morgan thinks he's got it covered but doesn't realize his plan is about to be unraveled by Izzy, who is set on getting to the bottom of what her pup does all day.