- The Avengers
- Fantastic Four
- Radioactive Man (Chen Lu) (Recaptured)
- Amora, the Enchantress
- Skurge the Executioner
- Malekith, the Accursed (Death)
- Loki (Loki Laufeyson) (Mentioned)
- Casket of Ancient Winters
- Iron Man Armor Model 8
- Captain America's Shield
- Captain America's Uniform
- Hawkeye's Bow and Trick Arrows
- Hawkeye's Suit
- Bloodaxe (Enchanted Axe)
- Ant-Man's Helmet
- Ant-Man's Suit
- Wasp's Suit
- Bio-Synthetic Wings
- Pym Particles
- Ant-Man's Ants
- Vibranium Energy Daggers
- Panther Habit
- Arc Reactor
- Avengers Identicard
A hooded man and his hired help make their way to a cavern in the icy north, which turns out to be a vault or a tomb of some kind as evidenced by the frozen frost giants. The guides either panic and run away or are killed and the stranger claims his prize: the Casket of Ancient Winters. Amora and Skurge show up to check on the man, revealed to be Malekith the Accursed, a dark elf who was, until recently, imprisoned in Niflheim. He turns on them and unleashes the full power of the Casket, covering the entire world in winter.
Meanwhile, it's a warm sunny day in New York. Hawkeye, Wasp and Hulk are enjoying the sun, so are reluctant to go assist Iron Man, Thor, and Black Panther who are caught up in a battle against Radioactive Man. After a brief skirmish, Radioactive Man begins draining power from the Arc Reactor in the Stark Industries building. Iron Man attempts to sink the reactor and Radioactive Man into the ground but Thor smashes the reactor's cooling pipes, opting to subdue him with large amounts of water instead. An argument breaks out when Thor starts ranting about the evils of mortal science but it has to be put on hold when snow starts falling over New York City. He recognizes the magic and explains the Casket's power. It turns out Odin hid the artefact on Earth long ago since it would be beneath the notice of most Asgardians.
Tony calls Thor out on how a magical artefact is causing just as much damage as human science, continuing the argument from before, and T'Challa deduces that the Casket is located in Norway, despite the fact that Stark was previously unable to determine any pattern in the magic's effects.The situation gets progressively worse as ice monsters start emerging from the snow. The rest of the Avengers fight back against them with the help of the Fantastic Four while Iron Man heads to Norway with Thor and Panther to stop the problems at their source. Iron Man and Thor continue to trade snarks about magic and technology.
The trio confronts Malekith, who promptly freezes Thor and announces his plan to turn Midgard into a new home for the dark elves. He then sics the hounds on Panther and Iron Man, and draws upon the power of the Casket to make himself unstoppable. Panther tells Iron Man and Thor in no uncertain terms that they will need to combine the strengths of magic and science if they hope to beat Malekith. Thor then hits Iron Man's armor with lightning, supercharging it, and allowing him to defeat the dark elf. With him out of the way, they are able to close the Casket and banishes all the spirits and ice monsters back where they came from. Iron Man and Thor manage to settle their differences but they are jumped by Amora and Skurge, who take the Casket. Thor attempts to return to Asgard and warn the other gods of the Enchantress' treachery but finds that the way is sealed. He can't go back.
- First aired in the United States on May 16th at 10:00 am.
- This is the first appearance of Human Torch and Thing in this series
- Hawkeye's statement that the Avengers should move to the West Coast is a reference to the West Coast Avengers, an offshoot branch of the Avengers in the comics. Hawkeye was the leader of this team for most of its duration.