"Piano Lesson!" is an episode of Oobi from the first season.
Oobi is at home, anxiously waiting for his first piano lesson. He is playing random notes on the piano and counting them. The doorbell rings and Grampu answers it. He sees Oobi’s piano teacher and is immediately attracted to her. She introduces herself as Inka and compliments Grampu's house. Oobi is both excited and nervous. Grampu offers Inka a drink and she requests tea.
As Grampu prepares a cup of tea, Inka tells Oobi that he must stretch his fingers before playing the piano. He does this as Inka plays a major scale. She asks Oobi to do the same, but he cannot. She explains that relaxation is key when playing a musical instrument. Inka plays the scale again, this time singing along with it. Grampu is an awe after hearing Inka’s singing voice. Oobi tries to play a scale again, but fails. Inka is told that her tea is ready. She tells Oobi to practice.
While she and Grampu drink their tea, Inka asks Grampu if he plays the piano. Grampu tells her that he can play, but not well. Inka examines his fingers and states that he must be a musician. Grampu is flattered and denies this. Oobi asks Inka if he can show him the scale again. She asks Grampu to show him instead. Grampu nervously agrees and plays the scale perfectly. After stretching, Oobi starts playing the piano and is astonished at his skills.
The three characters decide to play the scale together on different octaves. Inka sings along as Oobi and Grampu play together. Afterwards, Oobi thanks Inka. Inka mentions that she likes Oobi and is looking forward to his next piano lesson. Grampu, obviously in love with her, screams out "Grampu like Inka!" and quickly clarifies that he appreciates her efforts. Inka responds by telling Grampu that she likes him as well, confirming that they both have feelings towards each other.
After Inka leaves, Grampu leans against the door and begins to daydream about her until Oobi snaps him out of it. In an interview segment, Kako asks the viewers if they have ever taken lessons. Later, Oobi and Grampu play a stop/go game. Grampu plays the piano and Oobi dances. When the music stops, Oobi stops. Uma appears and asks if she can play the piano. She begins hitting random notes on the piano with her palm. Oobi and Grampu both agree that Uma should take piano lessons as the episode ends.