|Season 1, Episode 9|
|Air date||May 20, 2012|
|Written by||Man of Action and Eugene Son|
|Directed by||Alex Soto|
"Back in Black"
Midtown High students have taken a field trip to a museum, where Phil Coulson informs the class of a tablet that originated from Asgard. Peter, however, exclaims he hates field trips and recalls unpleasant memories as Ava, Luke, Danny, and Sam start staring at the tablet. Danny translates the tablet and it grows brighter until releasing a Frost Giant. Coulson quickly clears the room of witnesses and the team change into their costumes. The team struggle to work as one as their different fighting styles contradict one another. Eventually, they are saved by the arrival of Thor, whose arrogance prompts him to rebuff the young heroes' help. Thor uses Mjölnir to knock out the Frost Giant as Spider-Man and the team fight to tell Thor of their strong teamwork.
Thor leaves the conversation and spots an amulet around the Frost Giant's neck. However, Spider-Man tells him not to touch it since his spider-sense is going off. Thor's pride and arrogance proves his undoing as the mere touch of the amulet transforms him into a frog. Blaming his brother Loki, Thor decides to travel to Asgard, but Spider-Man forces him to swallow his pride and let him and his team help. Thor reluctantly agrees and they arrive at one of the nine realms. The six heroes are shocked to see Asgard completely cover in ice and are ambushed by seven Frost Giants. One by one, they are each frozen and imprisoned.
Inside the palace, the five heroes are encased in ice while Loki has Mjölnir and Thor in separate green bubbles. Iron Fist looks for the cage's weak spot as Loki boasts about allying with the Frost Giants and using Thor's pride as his weakness, and that he will kill Odin once he manages to break open the doors to his room. Iron Fist and Power Man break the cage and the heroes attack. However, Loki and the Frost Giants prove too powerful and Thor, reluctantly, flees with the team. They arrive in the outskirts, where Thor chides himself that a god should not run, but Spider-Man tells him that they had to or they would have been killed.
The team then ask if there is anyone who could help them defeat Loki, and Thor responds there is one person. He takes them to a cave where Eitri, forger of Mjölnir, resides. Thor pleads for his assistance, but Eitri refuses due to feeling underappreciated by Thor and the others who only visit to retrieve weapons and never say thank you. Spider-Man then tells Thor to challenge his pride, prompting Thor to reluctantly apologize and that Eitri was far better than he was credited. Obviously pleased, Eitri agrees to aid the heroes. Loki gloats in his victory as the door starts to crack, and Mjölnir spins in, revealing Thor. Unfazed, Loki exclaims he cannot be beaten, until the heroes arrive with new weapons, with the exception of Spider-Man.
Each member of the team battles with their respective weapon while embracing and utilizing Eitri's advice. Spider-Man finally takes command and leads his team in defeating the Frost Giants. Loki opens the door, but Spider-Man blocks his path and tricks him into transforming Thor. Thor then grabs Loki, but the latter flees, swearing revenge on Spider-Man. Thor reassures the group that Odin is still alive and sleeping before taking them back to Earth. Thor declares them to be heroes and rewards them with a two-headed goat, which bites Spider-Man's hand.
- Despite being addressed by his name in the episode, Eitri is simply listed as "Dwarf" in the ending credits.