: Jake disguises himself as "Prince Finn" (or a messenger for him) and visits the Flame King.

: The Flame King, believing Finn to be a ruthless killer like his daughter, releases Flame Princess from her lantern prison.

: Mistaking her slap for a sign of passion, Finn realizes he has a new crush. Key Character Debuts

" Incendium " is the season finale of Adventure Time ’s third season, famously marking the first appearance of . The episode serves as a pivotal shift in the series' romantic dynamics, moving Finn away from his unrequited crush on Princess Bubblegum and introducing a more complex, volatile love interest. Synopsis: A Broken Heart and a Fiery Cure

The episode begins with a heartbroken Finn crying over Princess Bubblegum's rejection. Desperate to help his friend, Jake travels to the Fire Kingdom to find a new princess for Finn.