- The Avengers
- Baron Zemo (Heinrich Zemo)
- Arnim Zola
- Doughboy (First appearance)
- The Enchantress (Amora)
- The Executioner (Skurge)
- Red Skull (Johann Shmidt) (Mentioned)
- Bucky (James Barnes) (Only in flashback)
- Dr. Abraham Erskine (Mentioned)
- Howard Stark (Photo)
- Captain America's Shield
- Captain America's Uniform
- Iron Man Armor Model 8
- Ant-Man's Helmet
- Ant-Man's Suit
- Wasp's Suit
- Pym Particles
- Ant-Man's Ants
- Grim Reaper's Scythe
- Satan Claw
- Super-Soldier Serum (Mentioned)
- Virus X
- Zola's Robotic Body
While in the midst of searching for the Hulk following his departure in the previous episode, Iron Man starts picking up a faint life sign but can't pinpoint its exact location. That's where Wasp comes in, although not quite in the manner that anyone had in mind. She does not find the Hulk but a shield with a red, white, and blue pattern, frozen in the ice. As it turns out, Captain America was not thrown into a watery grave but was somehow able to survive, albeit just barely.
The Cap is defrosted on board the quinjet and regains consciousness completely disoriented. Thinking that the Avengers are in fact HYDRA agents, he takes them all down and bails out over New York City; the decades he spent frozen in ice do not appear to have noticeably diminished his fighting skills or athletic ability. Meanwhile Black Panther acts on his own, inscrutable motives, breaking into Avengers Mansion and downloading details on all the heroes. Attempts to reason with Captain America end in failure, largely due to Thor's insistence on smiting first and asking questions later. The fight is only stopped when the Cap turns and notices that a large crowd of tourists has gathered to snap photos of the confrontation. Confused, he begins to realize that this is a world quite unlike the one he left behind after the Red Skull's escape a world where he and Bucky died.
The Cap's return also catches the attention of HYDRA, which is in the midst of a small leadership crisis now that its former leader, Baron Zemo, has escaped from the Raft. Upon hearing the news, Zemo decides to give up his claim, taking only the scientist Arnim Zola and declaring that he is only interested in revenge. The audience is then treated to a small flashback to World War II where Zemo was in charge of a bio lab in charge of creating monsters and an even more sinister weapon: Virus X. Captain America and Bucky destroyed the lab and Zemo was immersed in his own concoction, requiring regular treatments from Zola to stay alive. In the decades since the war, Zola's technology and capabilities have improved but he has not been able to find a cure for Virus X. He speculates that Captain America's DNA, enhanced by the Super Soldier Serum, might hold the key to a cure and the two friends begin plotting.
The Avengers take the Cap back to the Mansion, filling him in on what has happened to the world in his absence. He was an inspiration to the entire nation and left behind a great legacy, but this is a cold comfort to the Cap now that everyone he ever knew and loved is gone. He leaves to be alone with his thoughts while the Avengers respond to an emergency call back at Ellis Island, which is being menaced by Zola's giant blob monsters. One of them also attacks the Mansion, leaving Cap and Wasp to fend for themselves. Wasp's bio-stingers actually manage to take down the blob monster unlike the efforts of the other Avengers. She is unable to actually saver her victory thanks to the arrival of Baron Zemo.
Zemo's attacks take their toll on Captain America and he is hard-pressed to fight without his shield. Just as Zemo is about to deliver the coup-de-grace, however, the Black Panther shows up and tosses him the mighty shield, allowing the Cap to regain the upper hand. Zemo remains defiant, claiming that the future belongs to him but Cap rejects this sentiment.
The Avengers continue to struggle against the blob monsters, which have merged into one gigantic blob monster that keeps growing thanks to Thor's lightning. In his last moments, Thor is disturbed that mortal science could have created such a monstrosity but just when all seems lost, Cap and Wasp show up to help free the others. Wasp is once again the most effective combatant against the blob monster and Cap identifies the creature as one of Zola's creations. Ant Man is hit by a sudden inspiration and reconfigures his helmet to start emitting energy waves that drive the creature back. As it turns out, Zola's monsters all share a common weakness: they're really unstable and the right type of energy (like Wasp's bio-stingers) can exacerbate that instability. After Iron Man reconfigures his repulsors to give off the same type of energy, the monster is defeated. The cheering crowds that emerge convince the Cap that maybe, just maybe, he's not as obsolete in the modern world as he thought.
Later, Tony gives Cap an old keepsake of his: a photo of his father Howard Stark with Cap and Bucky. He also invites Cap to join the Avengers, which he happily accepts. Cap then asks to meet the Avenger who saved him during the fight at the Mansion, leaving Stark totally confused. Zemo returns to Zola's secret hideout to begin plotting his next move, but the Enchantress makes him an offer he can't refuse.
- This episode is based on Avengers #4.