Milo, Zack, and Melissa—with help from Phineas, Ferb, Candace, Buford, and Baljeet—help conquer Murphy's law to stop a swarm of Pistachions.

After an incident with a skydiving simulator, Milo, Melissa, and Zack are left in a cycle of falling and rising through the sky while Diogee tries to save them. Meanwhile, Cavendish and Dakota, while flying a plane and trailing a "Don't Litter Our Planet" banner, accidentally gain rivals in the form of Colonel Niblet and Lieutenant Tenant after taking the blame for Milo and his friends destroying one of their facilities.

Milo, Lydia, Coach Mitchell, and Scott get stuck in the Googolplex Mall elevator. Meanwhile, Doofenshmirtz and Dakota decide to finally attempt to search for Cavendish with the help of a "Cavenpus" clone made from Cavendish and Agent P's DNA.