First of all, Vinny the dog has replaced Brian in the opening credits. Weak.
A buzzing bee startles Quagmire and Peter causing them to shriek like a couple of scared girls. They notice that their shrieks sound kind of good, like maybe they could be singers. It actually sounds like one half of a barbershop quartet, but Family Guy couldn't do an episode like that, then they'd be blatantly ripping off a Simpsons episode.
Vinny is in his second episode. He's no Brian. Get rid of him, Family Guy.
Quagmire and Peter buy paper at Mort's store, prompting the tightwad owner to explain how he had experience managing Earth, Wind, Fire & Pollen back in the day. The duo decides to take Mort on as their manager.
Griffin & Quagmire's first performance is at a library. Their first song is about not being able to poop in public. After their performance, Mort books Griffin & Quagmire at the New England music festival. This time, their song is about putting butter on a Pop-Tart.
After the performance, a shady guy in a leather jacket promises he will pump up the careers of Griffin & Quagmire.
Peter abandons his family hoping to find great success on a road trip. He slowly develops a diva attitude, belittling Quagmire and worse, farting in a recording booth.
Meanwhile, the song lyrics continue to get more random. One talks about how a "waitress is prettier than my wife" and after that he will "kill his family with a knife." Another subject points out that you should never look at your mom and dad's private parts. Good advice.
During a live performance on Conan, Peter's guitar pick gets stuck. Of course, he screws around trying to find it rather than continuing the performance. This foolishness pisses off Quagmire, forcing a fallout between the duo. At the end of the episode, Peter goes back home and he even makes amends with Quagmire. Peter mentions that life after fame is always better. He goes back in the tour bus to grab his stuff. Instead, he apparently shoots himself in the face. We know Peter will be back in future episodes, hopefully the same can be said about Brian.