Beethoven emerges from the living portrait paintings of famous composers that inhabit the Music Room of St. Claire Elementary School. He stands among a group that includes Johann Sebastian Bach, Franz Schubert, and Wolfgang Amadeus Mozart. Together, they serve as guardians of one of the school’s challenges, which demands that participants compose a musical piece worthy of their approval.

He possesses a passionate and fiery temperament, quick to anger. This rage is vividly displayed when the main characters recognize only a fragment of his music—a call-waiting tone. Interpreting this as a profound disrespect, his eyes shift into a blank, startling white, a physical mark of his fury.

Within the narrative, he functions as an obstacle in the quest for the medallions. The challenge he presents is overcome not by musical expertise, but by chance: Mutsuko, one of the girls, makes a decisive strike on a single piano key while trying to catch a fly. The composers perceive this stark, minimal sound as a bold and original artistic statement, and they award the medal.