Phineas and Ferb plan to put Danville on the map by building the world's tallest building. However, Candace teams up with Albert and utilizes his expertise to bust her brothers. Meanwhile, Dr. Doofenshmirtz wants to be responsible for all the evil in the Tri-state area, and since he believes that evil levels rise during a full moon, he plans to rotate it so that only the infamous "dark side of the moon" faces Earth.

Phineas, Ferb and the gang are all sick with a cold, so they decide to make it the best "sick day" ever by creating a live television feed to their friends' homes so that they can all enjoy a day of fun together. Meanwhile, Vanessa learns from her mom, Charlene, that her dad is picking her up from a party she is going to with her punk rock boyfriend Johnny and is worried that he will embarrass her yet again. However, Dr. Doofenshmirtz is busy trying to use his "Deevolution-ator" to drain Agent P's will power so that he can control him, and things get out of hand when Dr. Doofenshmirtz picks up Vanessa at the party, and it's up to Agent P to save the day.