Phineas, Ferb, Isabella, Baljeet, Buford - and surprisingly Irving, the boy's "#1 Fan," - find one of the Evil Genius Doofenshmirtz' inventions. The invention, an Anti-love rocket, his second machine to foil love in the Tri-State area is to be used to eliminate romantic elements in 'said' situations. Also, through a flashback, it is said that Doofenshmirtz went on a blind date with a Pop Icon - Lindana - Phineas' Step-mother. For their project, they reverse engineer the Anti-Love rocket, making a duplicate, and try to find out what it does.
Meanwhile, Perry, and Doofenshmirtz are trapped - early on - in the skies of Danville and beyond. The booby traps keep them restrained, and they work together to escape - needing to get back to the Tri-State Area.
As for Candace, she, along with her mother, try to find out what the original - crashed - invention in the backyard is (the original Anti-Love Rocket.) It gets more complicated when Ms. Flynn calls Mr. Fletcher, her husband, and he misunderstands - thinking she meant a mechanical birdhouse he made. And... worst of all... Candace dances.
Not yet to Disney Channel / Disney XD US. Already on Disney Channel / Disney XD UK.