Adventure Time: Fionna and Cake season 2 episode 9 ending explained: What teases Jake's death?

Adventure Time: Fionna and Cake is a Max original spin-off from Cartoon Network's Adventure Time, developed by Adam Muto. Season 2 premiered on October 23, 2025. 

The series centres on Fionna (Madeleine Martin), a restless young woman and her magical cat Cake (Roz Ryan), as they navigate a restored magical world alongside Simon Petrikov (Tom Kenny), the former Ice King.

Episode 9, "The Worm and His Orchard," shocks viewers by teasing Jake's death as unnatural and traumatic. Fionna briefly glimpses Finn's largest unprocessed pain orb: a memory of Finn screaming Jake's name in horror. 

Fern intervenes, pulling her away and warning her she doesn't want to see the details. This implies violence or sudden loss, challenging prior assumptions of peaceful old age passing.

In season 2, Fionna and Cake adjust to life in Ooo while Huntress Wizard (voiced by Ashly Burch in key scenes) pursues an urgent mission linked to Finn's condition. 

In episode 8 we saw Fionna's hasty testimony at the Cosmic Court implicates Finn in the Cosmic Owl's death, resulting in his arrest. Cake manages a chaotic Boys Night solo.

Adventure Time: Fionna and Cake season 2 episode 9 ending explained- Chaos in Undergrowth with Fern’s return and Karmic worm’s friendship with Cake

The episode opens with Huntress Wizard entering Fionna's mindscape to locate a portal connection. Inside Huntress's memories, they uncover her backstory: as a child, her adoptive parents died in a house fire, leaving her with deep trauma. 

This shared emotional vulnerability activates a portal to the Undergrowth, a lush metaphysical realm where unprocessed painful memories from across the multiverse manifest as red orbs hanging on personal trauma trees.

Fionna arrives first, immediately trapped in a giant carnivorous venus flytrap plant. She is rescued by Fern, the grass demon-Finn hybrid/ finn's doppelganger from the original series marking his surprising return after dying in "Come Along With Me."

Fern explains that after his death, his consciousness ascended to the Undergrowth due to his strong connection to green magic and the grass curse. Here, he has found peace, fully embracing his unique identity separate from Finn. 

He now tends the realm's flora and specifically guards Finn's trauma tree, which is overburdened with unprocessed red orbs recalling events like Finn's arm loss, turbulent relationships and other repressed pains.

Meanwhile, Cake encounters the Karmic Worm, a large caterpillar-like entity that oversees the orchard. The Worm eats the red pain orbs, processes the trauma internally, and regrows them as positive memories that float upward to reunite with their owners, completing a cycle of healing.

As Cake bonds with the Worm over shared feelings of isolation and identity struggles, a major reveal drops: the Karmic Worm is the Cosmic Owl's long-lost conjoined twin brother.

Ancient cosmic forces separated them as punishment, forcing the Cosmic Owl to deliver prophetic croak dreams while the Worm handled trauma processing in exile.

Their chemistry grows, and Cake, feeling truly understood, chooses to stay in the Undergrowth to explore this new connection and her own inner truth.

Tension rises when Witch Wizard portals in, having overdosed on the Heart of the Forest's regenerative cure earlier in the season. The excess green magic has transformed her into a raging, monstrous entity. 

Huntress Wizard confronts and defeats her by forcing even more overload, causing Witch Wizard to collapse without killing her, showing mercy.

The episode's emotional core builds around Finn's trauma tree. Fionna approaches the largest, most prominent unprocessed orb. Touching it briefly triggers a vivid flash: Finn in absolute horror and agony, screaming "Jake!" desperately. 

This wham moment strongly suggests Jake's death involved foul play, violence, or something deeply horrifying- directly contradicting earlier hints of natural old-age passing. Fern reacts instantly, yanking Fionna away and sternly warning, 

"You don’t wanna see that one" 

The un-reveal heightens the mystery, implying the full memory is too disturbing even for Fionna, who never met Jake.

In a parallel climax, the Karmic Worm, learning of his brother's "death," intentionally breaks the Cosmic Owl's pain orb. This resurrects the Owl as a hatchling back in the Cosmic Court.

The reborn Owl confesses he staged his impalement as suicide-by-cop to escape his eternal prophetic duties. 

This exonerates Finn and Huntress Wizard of murder charges. Declaring croak dreams over forever, the Owl quits his role and flies off, altering cosmic balance permanently.

Fionna returns to her world alone via a portal. Cake stays behind with the Worm and Fern. Huntress Wizard remains trapped in the Undergrowth, unable to exit because Ooo's Heart of the Forest has died.

Back in Ooo, with Finn still comatose and options exhausted, Princess Bubblegum reluctantly contacts his mother, Minerva Campbell.

The Jake tease dominates the ending's impact: the orb's size and Finn's raw distress portray repression of a catastrophic event. Fern's intervention and "you do not want to know" line underscore its severity, setting up Finn's inevitable confrontation in the finale.

Fern's serene return closes his tragic arc, emphasising the Undergrowth's therapeutic purpose. The twins' reconciliation adds layers to cosmic lore, while character separations raise stakes.

What to expect in Adventure Time: Fionna and Cake season 2 finale:

With episode 9's revelations, the finale must address Finn's coma and repressed trauma likely forcing him to process Jake's death. Cake's stay separates her from Fionna temporarily, testing their bond. Huntress Wizard's entrapment needs resolution.

The Cosmic Owl's retirement alters cosmic prophecies. Minerva's involvement hints at technological or familial aid for Finn.

Where to watch Adventure Time: Fionna and Cake season 2 

Adventure Time: Fionna and Cake season 2 streams exclusively on Max. The finale drops on December 25, 2025.

Stay tuned for more such updates!