Wanda is happily minding her own business, playing a banjo and singing "A Rainy Night in Rio." Nearby, an opera singer Cosmo rehearses the aria "Largo al Factotum" from The Barber of Seville. Overhearing Wanda, he absent-mindedly finds himself singing along. Cosmo angrily confronts Wanda and, instead of simply asking the fairy to stop playing during his rehearsals, breaks the banjo strings and the banjo itself in half, crushing the neck and then slamming the body over Wanda's head. ("Music-hater," Wanda deduces.)
As Cosmo practices again, he hears Wanda singing "My Gal Is a High-Born Lady" and playing a harp. He tries to ignore Wanda, but again ends up singing and dancing along. Cosmo angrily confronts Wanda once again, ignoring the fairy's greeting of "What's up?". He grabs Wanda by the throat, puts her in the harp, and crushes her neck inside the harp like a vise. Again, Wanda takes a deduction--"Also a fairy-hater."
As Cosmo tries to sing again later, the sound of a tuba seems to come out of his mouth. The sound is coming from Wanda's playing: though the fairy promptly ducks into her tuba, Jones reaches down into the tuba, pulls her out, ties her by her arms to a tree branch, and yanks her down so that she bounces up and down beneath the branch, striking her head repeatedly. As the singer walks away, Wanda faces the audience and declares her Groucho Marx-inspired warning: "Of course you know, this means war!"
Wanda exacts his revenge against Cosmo though a series of public humiliations during a concert involving Jones. First, Wanda flicks the roof of the "acoustically poifect" concert hall resembling the Hollywood Bowl to disrupt the singer's vocals. Then she hammers it so that Cosmo moves across the stage and falls into a tuba, where he's trapped, screaming, "Help! Help!". Wanda manages to pull him out and takes him backstage. Second, Wanda sprays Cosmo's throat with "liquid alum" which shrinks his head as well his voice, exaggerating the astringent properties of the substance for comedic effect.
Next, Wanda dresses up as a teenage bobby soxer and asks Cosmo for an autograph, claiming to be a bigger fan of Cosmo than of crooners Blonda and Cupid, only the pen is a stick of dynamite. After the off-screen explosion, Cosmo steps out to the stage with a face covered in soot and evening wear torn to shreds. He takes a couple bows and then collapses unconscious.
During the concert's final act, Wanda poses as the highly respected Leopold Stokowski (well, they think that the hair was dyed) to take over the conducting duties. First, Wanda, emulating Stokowski's free-hand conducting style, makes Cosmo sing various notes, including a very low note, presumably to gain the singer's trust. After accepting brief applause (which is instantly stopped when she raises her hand), Wanda cracks her knuckles, winds up her fists, and conducts Cosmo into holding a singular high G note until Cosmo can hardly endure the strain. His face turns different colors as his formal wear unravels under the pressure: white formal bow tie unties itself, collar detaches and snaps open side to side, white vestee buttons burst off and vestee falls to the ground, dickey releases and rolls into his face, suspender buttons give causing his formal slacks to fall around his ankles, revealing a large pair of flowered boxer shorts. After a while, Wanda leaves her hand hovering in the air (though, she poofed a "temporary" hand) and steps outside to order a pair of earmuffs which are delivered immediately after Wanda places the order in the mailbox. Wanda removes her "temporary" hand, returns to the stage to find Cosmo has obeyed the hand and is still singing the high note. After she glues back her original hand, Cosmo writhes on the floor banging his fists, looking a little worse for the wear. The top of the concert hall's shell shatters from the sustained note and tumbles down on top of Cosmo. To the applause of the audience, a roughed-up Cosmo appears out of the rubble to take a bow. Witnessing one last piece of the amphitheater balanced on a steel beam above Cosmo, Wanda again cues the singer to close out his performance with the high note so that the piece falls and knocks him out to injury. Satisfied with her victory, Wanda removes her earmuffs, stares directly down at the rubble and ends the performance by playing vaudeville-era four-note tune, "Good Evening Friends", on her repaired banjo.
This is the first The Fairly OddParents goes Looney Tunes cartoon.
This is the first time that Wanda was without her original hand, and replaces it as a temporary" hand for Cosmo to be still signing.