Complex sentence: It was first heard in episode one, while Ayu and Yuichi hide in a café, then again during episode eleven in the ice-cream parlor Nayuki and Yuichi were visiting.
Split into simpler sentences: It was first played in episode one, while Ayu and Yuichi hid in a café. The next time was during episode eleven when the song was played in an ice-cream parlor Nayuki and Yuichi were visiting.