Adventure Time: Fionna and Cake season 2 episode 4 ending explained: What is Simon's last resort to save Finn?

In Adventure Time: Fionna and Cake season 2, the show continues the multiversal storytelling that began with the original adult animated spin-off created by Adam Muto for HBO Max. A direct expansion of the Adventure Time franchise, this series serves as the third main installment, premiering in 2023 with its second season debuting on October 23, 2025. The series follows Fionna the Human and Cake the Cat, alternate-universe versions of the beloved duo from the Cartoon Network series.

The latest episode of Season 2 escalates the urgency with Finn’s worsening condition in Ooo, pushing Simon, Princess Bubblegum, and Marceline toward drastic measures, setting the stage for Episode 4’s dramatic ending.

Simon turns to forbidden magic to save Finn

Episode 4, titled The Cat Who Tipped the Box, threads together several emotional storylines, but the highest stakes belong to the crisis unfolding in Ooo. Finn is alive but trapped in a fragile stasis after being gravely injured in the previous season. Princess Bubblegum gathers the crown jewels and brings Marceline and Simon to Prismo’s realm, convinced that only a cosmic wish can save him. But Prismo is powerless. He reveals he has no remaining “wish dazzle,” making wish magic temporarily impossible. Simon grows increasingly frantic, begging Prismo to do something, anything, to save Finn. But the truth is unavoidable: Prismo’s magic is gone, and Finn’s condition remains dire.

With no other options, Simon remembers something he hoped he’d never need again. He travels to the Ice Kingdom to seek the Demonic Wishing Eye, a corrupted magical artifact once associated with the chaotic powers that contributed to his tragic transformation into the Ice King. It’s now guarded by the Ice Thing, a grotesque variant of Gunther, who only hands over the eye after forcing Simon to watch him perform an extended drum solo.

The final scene reveals Simon quietly holding the Demonic Wishing Eye, preparing to make an emergency wish for Finn’s recovery. The series heavily implies that Simon knows the risks: the eye’s twisted magic could harm him, reawaken old powers, or warp reality itself. Still, he’s willing to take the chance. The ending makes Simon’s mindset painfully clear that he intends to use the demonic eye to try to save Finn, despite having no idea what consequences the corrupt wish might unleash. Finn’s fate as well as Simon’s, remains uncertain, leaving Episode 4 on a tense cliffhanger.

Recap of Adventure Time: Fiona and Cake Season 2 Episode 4

The episode opens with Huntress Wizard’s dark fairytale origin: an orphan raised by a kind huntsman who dies saving her from a fire. Reborn in Fionna’s world as a tiny plant creature, she hunts for food, grows rapidly, and eventually regains her humanoid form after Fionna feeds her. Triggered by memories, she realizes she must reach the Heart of the Forest to return to Ooo and save Finn. Meanwhile, Fionna spirals through a chaotic day as she chases memories of her ex, DJ Flame. She revisits their old haunts in flashbacks, reliving past happiness even as her present crumbles. She misses Hunter’s parks department meeting, runs into DJ Flame’s girlfriend, and ends the day with an eviction notice on her door.

Cake’s storyline provides comedic contrast as she answers a call for a cameo on Cheers. However, the set is literally a tiny box, and the producers pressure her to stretch into a dragon form. Overwhelmed and typecast, she accidentally destroys the set and flees. In the final moments, Huntress Wizard collapses muttering about the Heart of the Forest, Fionna’s phone is shattered, the apartment is locked with an eviction notice, and Simon quietly prepares to make a forbidden wish.

The episode ends with both worlds in crisis, emotionally, magically, and cosmically, as Finn's fate hangs in the balance.