- “Everyone is angry at me because I made a choice. A lot of you think it was the wrong one. Well, it wouldn't be the first time, and it won't be the... well... maybe it'll be my last. The truth is, I'm still figuring out how to do the right thing. I'm not using that as an excuse; I accept full responsibility. But before you condemn me, lemme ask: who here hasn't made a mistake? Yes, I went into the bridge to save Claire's brother, and if I'm being completely honest, I would do it again!”
- ―Jim's speech during his trial against the Troll Tribunal
Jim's trial starts. Usurna repeats all the charges. Blinky says they'll fight them. If convicted, he'll be exiled to the Deep, a place of unknown madness. No troll has ever returned from it. Blinky tries to convince Jim not to fight the charges, but Jim says he has to because of Merlin's visit. Blinky thinks he's nuts and won't represent him, but Vendel says he must be represented by his own tribe, meaning Claire or Toby. He decides that Toby will represent him. They give him time to prepare his case.
Blinky piles Toby up with books to help him. Claire's not sure how Toby can defend Jim because they did let Gunmar out and they are guilty of that. Toby remembers that Gunmar has a spy in Trollmarket. They need to prove that he's working with that person and it's not their fault. Toby's job is to stall while they figure out who it is.
Claire and Blinky try to figure out how to find Gunmar's accomplice. They use an idea from the law show Toby watches with his grandma.
Toby steps forward and enters a plea of not guilty for Jim. He tries to get Gatto removed from the panel, but Usurna says objections aren't allowed under Troll law. Toby declares that Jim is guilty as charged. Jim is shocked, but Toby claims he has it handled. As he finishes his speech, the Tribunal starts to throw rocks at him. Gatto's rock hits first, so he gets to speak first.
Blinky and Claire go to RotGut's. Claire wants to play Good Cop, Bad Cop in order to get what they need. She starts off as the Bad Cop, trying to get the information they need. She then steps aside and tells them to deal with Blinky. Blinky threatens them with a weapon, causing them to hide inside. Blinky thought he was supposed to be the bad cop. Rot and Gut decide to give up the information and say it was Krax who bought out their supply of gaggletacks. Blinky realizes the mole might be a changeling.
Toby interrogates NotEnrique, who is more interested in getting the sock Toby has. The Tribunal throws rocks again to stop him. They want to hear NotEnrique, not Toby. NotEnrique says Jim's a good guy, a hero. He starts to say too much, so Toby gives him the sock to shut him up. Usurna orders him to finish his statement. NotEnrique continues, saying that if Jim hadn't been Jim, Gunmar would have never gotten out. Jim asks the Tribunal to testify for himself, but it's not allowed under Troll Law. Vendel tells him to speak anyway. Jim accepts full responsibility, but says everyone has made mistakes before. He went in to save Claire's brother and he would do it again. The Tribunal leaves to go rule on it.
Claire and Blinky are looking for something incriminating at Krax's place. Claire finds gaggletacks, but that's not enough. Just then, Krax arrives at home. Blinky throws a gaggletack at him, revealing a human form. Krax tries to leave, but Blinky stops him and threatens him with a Dwärkstone. Krax tries to get the stone away from him, but has to chase it. It explodes, killing him and leaving them without a lead. Blinky realizes they're covered in Krax and race to show the Tribunal.
They arrive at the trial to learn they're too late. They insist that they need to speak to Vendel.
Blinky tells Vendel about Krax and says the dust on them is proof of the conspiracy. Gunmar's escape was only a matter of time because of Krax. They plead with Vendel to take the evidence back to the Tribunal. Vendel believes them and agrees to talk to Usurna.
Usurna and Vendel walk and talk. Vendel says they must suspend the Tribunal and deal with the real threat. He believes Gunmar has more than one ally there. Usurna tells Vendel he's wrong. There are only two agents of Gunmar's in trollmarket: Krax and and his master. She's the master. She stabs Vendel and he starts to turn to stone quickly. She pushes him back so he shatters and then walks away.
Usurna calls the Tribunal to order and they realize Vendel's not there. They ask about him and Usurna says he said nothing of consequence when she spoke to him. Toby tries to object to Vendel's absence, but Usurna declares him guilty and sentences him to exile in the Deep, to face death by his greatest fear. Jim is taken away in his cage. They follow him and Jim tells them they tried. Merlin told him he'd have to fight and he's going to fight. The cage stops over the Deep, then Jim is dropped down.
At the bottom, Jim leaves his cage. He uses Daylight to light his surroundings. He hears growling, but doesn't see the source. Finally, he comes face to face with a monster that looks like himself, but as a troll. They fight and the troll gets him pinned.
The others try to convince themselves that Jim is going to be okay.
Blinky goes to look for Vendel and finds him turned to stone and shattered.
- Kelsey Grammer as Blinky
- Anton Yelchin as Jim Lake Jr.
- Charlie Saxton as Toby Domzalski
- Lexi Medrano as Claire Nuñez
- Fred Tatasciore as AAARRRGGHH!!!/Krax
- Anjelica Huston as Queen Usurna
- Brook Chalmers and Tom Kenny as Rot and Gut
- Grey Griffin as Queen Wumpa/Bork
- Victor Raider-Wexler as Vendel
- Jimmie Wood as NotEnrique
- This is the second episode in which the setting takes place solely in Heartstone Trollmarket, never once showing Arcadia Oaks. The first being "Something Rotten This Way Comes", the Part One season finale.
- It is revealed that Usurna is actually working for Gunmar and was the one who actually helped him escape all along.
- When Jim was exiled to The Deep, he confronts a monstrous troll version of himself with the Eclipse Blade. Aaron Waltke on his Twitter page confirms that the creature Jim confronts in the Deep is, in fact, a manifestation of his deepest fear: losing his human life and becoming a monster.
- Vendel is tragically killed by Usurna in this episode to prevent him from clearly Jim's name.
- Title: The title refers to the phrase "trial and error", which is the process of experimenting with various methods of doing something until one finds the most successful. Also, a "mistrial" is an inconclusive trial that is rendered invalid through an error in the proceedings, when the jury cannot agree on a verdict.
- It also refers to Toby's favorite fictional crime show series, Mistrial and Error, which is constantly mentioned throughout the plot.
- In a "blink-and-you'll-miss-it" moment, when the tribunal does their first round of rock-throwing at Toby and AAARRRGGHH!!!, a gnome can be seen flying by Toby as one of the objects tossed.
- Error: When Usurna smashes Vendel's body, the head piece rolls face down on the floor but as Blinky later found him dead, it was atop the pile of rubble.
- Running Gag: Blinky threatening to blow trolls up using dwärkstones.