With General Morando searching for Gaylen's Core, Aja and Krel must travel into their parents' subconscious to learn the core's location first.
With General Morando determined to learn the location of Gaylen's Core, Aja and Krel must hurry into their parents' memories to find the core first before Morando. Meanwhile, Varvatos, Steve, Eli, Toby, AAARRRGGHH!!!, Momblank, and Dadblank must escape Kubritz's captivity and venture back to Arcadia to save the royal children.
Mother explains what Aja and Krel will be doing as Morando accesses their memories himself.
Morando listens as the king and queen talk about Gaylen's core. It rests in the hands of its guardian. He takes his weapon and slices them.
Aja and Krel enter their parents' memories. They're surrounded by balls of memories. There are over 7000 memories relating to Gaylen's core. The most recent is from the day of the coup. They enter the memory and find that Morando has already been there and is destroying the memories. Aja and Krel have an advantage over Morando because they know their parents well enough to find the right memories before Morando.
The humans, Varatos, and AAARRRGGHH!!! are in a truck being taken to Area 49-B with Rickly and Lucy. Lucy cuts a hole in the truck and they all escape.
Aja and Krel watch the king tell the story of Gaylen. Seklos sacrificed her life core to stop him. Aja and Krel from the memory have fallen asleep. Krel makes the mistake of touching something in the memory, corrupting it. It's destroyed. They select another memory and enter.
Kubritz is angry to discover they've escaped.
Varvatos says they're far away form Arcadia. Stuart isn't answering. Varvatos wants Toby to call Nana to come get them.
Nana directs Toby as he drives them home.
Aja and Krel watch the Zeron Brotherhood try to steal Gaylen's core. Zadra helps the king and queen get it back. Aja is impressed with her mother's warrior skills and asks why she never told her. She's startled when her mother seems to look at her. The king and queen prepare to take the core off the planet. They take the mothership to Earth. Aja realizes they're in Arcadia near the kissing tree. Mother's memory of this placement was wiped, but she believes she was programmed to take them to Earth for this reason. The king and queen meet with a Trollhunter, Kanjigar the Courageous, and Vendel. The king and queen entrust the core to Kanjigar. Aja and Krel now know the core is in Trollmarket. Just then, Morando appears and corrupts the memory. They flee from Morando as he fires on them. Aja realizes they need to fight him to protect their parents. Morando gets the upper hand against them, but then the memories start to attack Morando. Their parents are protecting them. They defeat Morando.
Back in the world, Morando orders and Omen blank to sweep the ship and confirm all the royals are dead. Mother protects the king and queen in their stasis chambers from Morando, but Morando manages to disable the stasis chambers.
Aja and Krel manage to get out of the memories. They plan to go to their parents.
Outside, the humans, trolls, and Arkiridions arrive to help. Toby and Steve hold off the Omen blanks so Varvatos can go inside.
Aja, Krel, and Varvatos rush to save Mother and their parents.
Morando tells Kubritz he learned the location of the core and tells her to send his Omens.
Krel is working to get the pods to start working again. He doesn't think there's anything else he can do. He and Aja hug and cry. Mother has an idea. Her energy reserves might be enough to power the stasis chamber. But it will erase her forever. Aja begs her not to, but Krel knows there's no other way. Mother says she's learned so much about love and sacrificing for those you love. Mother is at peace with her decision. She restores power to the stasis pods. It saves their parents.
- Tatiana Maslany as Aja Tarron/Queen Coranda
- Diego Luna as Krel Tarron
- Nick Offerman as Varvatos Vex
- Glenn Close as Mothership
- Alon Abutbul as General Morando
- Uzo Aduba as Colonel Kubritz
- Hayley Atwell as Zadra
- Darin De Paul as Zeron Alpha
- Andy Garcia as King Fialkov
- Cheryl Hines as Momblank
- Tom Kenny as Dadblank
- Laraine Newman as Nana
- James Purefoy as Kanjigar
- Victor Raider-Wexler as Vendel
- Cole Sand as Eli Pepperjack
- Charlie Saxton as Toby Domzalski
- Fred Tatasciore as AAARRRGGHH!!!
- Frank Welker as Luug
- Steven Yeun as Steve Palchuk
- Mother sacrifices herself to reinitialize the stasis chamber so King Fialkov and Queen Coranda can continue healing.
- It is revealed that hundreds of years ago, Fialkov and Coranda had entrusted Kanjigar the Courageous to look after Gaylen's Core after it was nearly stolen by the Zeron Brotherhood on Akiridion-5.
- They have also preprogrammed the Mothership to travel specifically to Earth in the event of an emergency, just in case their legacy ever needs to reclaim it, which Mother herself seems to admit. This pretty much justifies Morando's previous theory from "Mother's Day", regarding why the royals were really sent the Earth.
- It is also revealed that Akiridions can live up to hundreds (or even thousands) of years, much like Trolls.
- It's implied that the Akiridions and Trolls are connected through an ancient prophecy all along.
- When Aja reads off from the kissing tree hundreds of years ago, the only initials on it is RB + CH. This could be a possible allusion to the executive producers of the franchise, Rodrigo Blaas and Chad Hammes.
- Title: The episode's title is a reference to the 1946 film noir of the same name, and by extension the 1939 novel from which the film is based.
- Continuity: Fialkov lampshades Kanjigar's title as "Trollhunter" by stating, "Just so I'm clear, you're a Trollhunter, but you're also a troll. So, does that mean you hunt yourself?" Toby also asks this similar question in the Trollhunters episode "Wherefore Art Thou, Trollhunter?"
- When thinking of ways to reinitialize the stasis chamber, Aja suggests unplugging the pods and plugging them back in, which is a nod to the common phrase "Have you tried unplugging it and plugging it back in again?" Krel lampshades this by saying that such a solution is not applicable to every technical issue.
- When Kanjigar says "For the glory of Merlin, Daylight is mine to command", Aja finds it familiar. It could possibly be a residue memory from "D'aja Vu" since it was the only time she's ever heard Jim say the incantation.