The first episode is "Boyfriend from 27,000 B.C." where the two boys unfreeze a caveman from a local glacier, just as Candace prepares for a costume party as a cave-girl, thinking Jeremy is going to meet her there dressed the same way. He does, but when a hungry, horny caveman sees a pretty girl with food dressed in the same attire before Jeremy gets there, it's a safe bet there's going to be some trouble.
However, like the second act of the Warner Bros. classic cartoon "A Corny Concerto," the second episode proves to be the superior tale. Phineas and Ferb are on the beach, when out of nowhere they see Buford doing something they never saw him do before -- bawling like a baby, and all over a lost pet goldfish. Buford explains how having the pet goldfish turned him from a victim of bullies into a bully himself. Instead of a montage for the main characters, we see one for Buford, punctuated, and dare I say exploited by a 1970's style "soft rock" tune.
From then on, Phineas decides he and Ferb are going to spend the day finding that fish, and Isabella and Baljeet join them. On a lighter note, Dr. Doofenshmirtz is caught on the local Danville TV News accidentally saving a kitten from a tree, and is assumed to be turning good by whatever agency Perry works for. Fearing that this incident might soil his reputation with other evil scientists, he wants to eliminate all media so they don't see it. Never mind the fact that the way the media works, it would've gone beyond Danville in less than an hour. And then of course, there's the routine attempt by Candace to bust her brother and step-brother, which fails as usual. Does she succeed? Of course not. Does Agent P defeat Dr. Doofenshmirtz? Naturally. Do Phineas and Ferb's elaborate activities prove to be worthwhile, obviously. Does that make it a routine tale? Not necessarily.