This is a season 1 Browne Boyz episode.
Carter gets a note in his locker at the high school regarding a "secret admirer" who turns out to be crazy-obsessed "number-one fan" Cassie. When Carter goes to the mall and meets Cassie there, Sabrina must take action. Meanwhile, Logan and Brooke have a bet to see who can go the longest without saying "I don't know" after Brooke gets annoyed by Logan using the phrase too much. The loser of the bet has to stand on top of a lunch table and sing the Oinkle Bear theme song.
This is Cassie's debut.