When the Diffys find a Caveman who stowed away in their Time Machine, they agree to make him a part of the family. But after Curtis attacks Mr. Hackett at school, Lloyd decides he must go. Lloyd gets lost while scouting a new location but Curtis' instincts lead Phil and Keely directly to him. In turn, Lloyd brings Curtis back home. Pim attends Debbie's sleepover.

Phil blows off the family's annual Unification Day celebration to attend a cool 11th grade party with Seth, Keely & Tia. The girls get in and the guys are only welcome if they can fix the backed up plumbing so Phil returns home and realizes that playing a traditional game of laser squash with Dad is truly more fulfilling. Pim's cheat on her home-ec assignment to make a home-cooked meal turns into a 400-pound Uni loaf!

Phil uses the "insta morph" to duplicate the image of Keely's new crush.

Sibling rivalry comes into play when Phil and Pim are left home alone and Phil is in charge. In an effort to prevent Phil from receiving the afterburners he longs for if things run smoothly, Pim runs, well flies, away on the skyak. After crashing, Phil rescues her from a cliff and Pim realizes how much he cares. Lloyd and Barbara take an old fashioned "road trip."

Phil comes to Pim's aide when he learns she's being bullied only to encounter the bully's older brother, Myron an even bigger bully. With the use of their futuristic Invisi Spray, they overcome their troubles. Lloyd is busy trying to replace Mandy Teslow's lawn ornaments that Curtis decided to bring home.

Phil's poor penmanship lands him back in Miss Winston's 2nd grade class and in Tanner's hot seat to expose embarrassing moments. While there he is videotaped by a 2nd grader named Crash, unaware that he's Tanner's younger sibling. Pim's new found guilty conscience gets the best of her when she uses Debbie Berwick to cheat.