The boys build a biodome to help the Fireside Girls. In "Canderemy", Candace's day with Stacy is complicated when, thanks to Dr. Doofenshmirtz, she is fused together with Jeremy.
Candace uses boots that Phineas and Ferb invent to be in two places at once. / A retiring train conductor inspires Candace to become determinedly lackadaisical.
Phineas and Ferb have become boring, and Perry fears he knows how. Doofenshmirtz stresses from Vanessa walking in on a conversation where he sounded like he'd rather have a son.
Candace is bitten by a bat. Phineas and the gang wind up in the best haunted house ever. A mad scheme leaves Dr. Doofenshmirtz adversely affected by the full moon.
Phineas and Ferb decide to create their own language - Ferb Latin - and later end up creating a hybrid race while addressing a potato famine caused by Doofenshmirtz.
The boys decide to put on a traditional family Christmas special featuring their family, friends and a few very special guests, including Kelly Clarkson.
It's the stone age and Phinabunk and Gerb decide to invent the wheel. It's 16th century China and Phineas and Ferb set out to rescue kidnapped Princess Isabella from Doofus Khan.
Phineas and Ferb are inspired by an antique escape chamber. Perry becomes Doofenshmirtz' butler, and the boys make a backyard amusement park out of cheese.
In "Let's Bounce", the boys use an anti-gravity device to suspend trampolines all over town to bounce on. In "Bully Bromance Breakup", Buford breaks up with Baljeet and joins up with Dr. Doofenshmirtz instead.
An errant blast from Doofenshmirtz' Babe-inator turns Phineas and Ferb into toddlers with Candace in charge of them. "Raiders of the Lost Ark" is spoofed.
Vanessa and Major Monogram's son, Monty, have coffee together. For a special Ducky Momo figurine, Candace makes multiple deals through Danville's annual Antique Show and Swap Meet.
While Evil Carl seeks Agent P's paw-print to unlock the OWCA computer, Dr. Doofenshmirtz teams up with Major Monogram to track Carl and build a Re-Good-inator.
Danville learns that Crikey the Crocodile has gone missing, Candance wants to get her hands on Irving's digital scrapbook, and the boys present alternative TV programs.