Loki, the Norse God of mischief, floats down from space. He finds himself in the place, not knowing why and how he has come here. He senses his brother Thor, God of Thunder and hatred flows through him. He fails to detect the presence of Asgard and its ruler, all father Odin. Loki is initially disturbed, but knows that the right moment to rid himself of his brother is now. He speeds towards Earth.
Loki travels down to Norway. He spots a group of archaeologists searching for a lost city. But his attention is suddenly diverted, when one of them spots the frozen form of the God of Thunder. As they near it, Loki casts a mystic blow. It fails however, to crack open the amber. As Loki curses his failure, one of the archaeologists mentions the name of the Avengers. The name sounds familiar to Loki, but he fails to remember any past happening. He plans to see the Avengers for himself and travels to New York.
New York harbor. Loki spots the room of Scarlet Witch and her mentor, Agatha Harkness. He comes inside, invisible to their senses. Wanda is attracted to Captain America, mentioning his handsome features. Agatha warns her to remember her values. Suddenly, Wanda senses Loki’s presence. She cannot define what she senses, but Loki knows that Wanda is a far more powerful sorceress than Agatha. He leaves quickly.
Next, Loki goes to the other Avengers’ rooms one by one. He spots the Swordsman, looking at his image in the mirror. He is intrigued by the appearance of Hellcat. The Vision’s robotic body draws his interest. He spots Hawkeye, training hard. Last of all, he goes to Captain America’s room. Captain recounts his past life, musing sadly. Loki travels to the meeting room. He sees Nick Fury, director of the Avengers and quietly praises him for his strong willpower. Nick reminds him of Odin. But suddenly, a call interrupts them all. The archaeologists report from Norway, saying that they may have found the frozen form of Thor. Nick is surprised, but decides to send his team, the Avengers to inspect.
Elsewhere, Wanda greets Vision and takes a tour with him around the facility. They meet Dr Henry Pym and his robot, Ultron. His wife, Ms. Janet Van Dyne comes forward and greets Wanda, praising her dress code and ravishing looks. Ultron calls Janet, his mother, and she starts shouting. But suddenly, an alarm sounds. Vision and Wanda go out, and find the other Avengers headed towards the meeting room.
Later, the Avengers travel to Norway. They meet the team of archaeologists and are shown the frozen form of Thor. Captain America orders his team to break open the casing. Hawkeye’s and Swordsman’s attacks fail. Captain strikes the amber with his shield and the Vision phases inside with it. He solidifies inside and cracks open the Amber. Thor comes out, groggy with sleep.
Loki, who has been watching them for some time now, decided to turn the situation to his advantage. He appears before Thor and taking advantage of his seeming amnesia, strikes friendship with him, turning him against the Avengers. Thor proceeds to attack the Avengers, while Loki turns his attention towards his true target, the Scarlet Witch. The Avengers quickly learn his motives and try to block him. Loki fires a mystic bolt, but Captain America shields Thor. Thor discovers his Mjolnir lying there and as he picks up, memories come flooding back to him. He turns his attack on Loki. As Loki opens a portal to Limbo, Wanda casts a Hex spell. This backfires Loki attack, and he himself disappears into Limbo.
Captain America requests Thor to remember his past. Thor partially remembers the Onslaught event, but too many fragments are amiss to clear his doubts. Captain America asks him whether he would like to join the Avengers, and Thor agrees at once.
Loki finds himself in Limbo. He sees the Enchantress speaking to him. Loki tries to strike a bargain with her, saying that if she returns him back to Earth, he will slay the Avengers. The Enchantress modifies the bargain. She asks Loki to kill everyone, except Scarlet Witch, who happens to be her daughter.