Sara wants to go see The Doctor Zone Files movie with Milo, but worries about potential problems.

Milo and his friends visit a dude ranch. While horse back riding, they meet a girl named Jackie who joins their posse, and Zack is smitten with love. But, Jackie leads them into more danger than usual. Meanwhile, Sara is going crazy because the ranch reminds her of scenes from The Doctor Zone Files, and invites other fans to join in the geek fest.

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