In this episode of Phineas and Ferb, Isabella's cousin Adrian comes to Danville to see Isabela's friends, Phineas and Ferb. Phineas and Ferb meet Adrian and tell him if he has any ideas of what to do today, then suddenly, he has an idea! His idea was to build a carnival. They go with the idea but then Adrian is missing! Meanwhile Adrian and Perry are given a mission to stop Dr.Doofenshmirtz, meanwhile Phineas and Ferb get help from the Fireside girls to build the carnival. At the end of the day, Adrian and Perry stop Dr. Doofenshmirtz and use there jet packs to land in the carnival. Phineas, Ferb, and Isabella stared at them in amasement! Adrian and Perry admit it, they are agents (accept Adrian is an agent in training) Adrian promises them if they have a mission tomorrow, they'll be in it. Tomorrow, in the morning, there's a mission. When they got in the base, Major Monogram is surprised to see them! Adrian lies to him and says there agents in training. (To be continued...)