Complex sentence: When one of the friends could not go, they gave their ticket to the nine-year-old Ulrich, who was mesmerized by the performance and bought the band's album "Fireball" the next day.
Split into simpler sentences: When one of the friends could not go, they gave their ticket to the nine-year-old Ulrich. Ulrich was mesmerized by the performance, buying the band's "Fireball" album the next day.