WHAT IF... ZOMBIES?!
In the Quantum Realm, Hank Pym finds Janet van Dyne, but she infects him with a quantum virus. They subsequently return to Earth and cause a zombie apocalypse. Two weeks later, a group of survivors—Bruce Banner, Hope van Dyne, Peter Parker, Bucky Barnes, Okoye, Sharon Carter, Happy Hogan, and Kurt—learn there is a potential cure at Camp Lehigh. They lose Hogan, Carter, and Hope to zombie attacks on the way there, but encounter Vision and learn his Mind Stone can reverse the virus, exemplified by a cured Scott Lang's head. However, they discover Vision has been luring people, such as T'Challa, to feed a zombified Wanda Maximoff, who is immune to the cure. The group rescue T'Challa, but Maximoff breaks free and kills Kurt, Okoye, and Barnes. Vision commits suicide while giving the Mind Stone to Parker. Banner transforms into the Hulk and sacrifices himself to battle Maximoff, allowing the others to escape. In the hopes of globally broadcasting the stone's energy, Parker, Lang, and T'Challa travel to Wakanda, where a zombified Thanos wields a nearly-complete Infinity Gauntlet.

EPISODE 1
Five years after a zombie virus devastates Earth,[a] Kate Bishop, Riri Williams, and Kamala Khan survive together in New York. When they find a shrunken device inside a zombie S.H.I.E.L.D. agent, they travel to a S.H.I.E.L.D. base in Ohio to activate it. En route, they unknowingly enter the fighting between Ikaris and a zombie Carol Danvers. Carol incinerates Kate, while Riri is bitten by a zombie. Riri and her artificial intelligence F.R.I.D.A.Y. sacrifice themselves to take Kamala away from the battlefield, where she is saved by Blade Knight, who takes her to Ohio. Upon arriving, they encounter Melina Vostokoff, Alexei Shostakov, and Yelena Belova, who have taken refuge and are guarded by Melina's controlled zombies. They determine that the device is a transmitter that must be used in outer space to broadcast a signal to the Nova Corps. The base is attacked by a zombie horde led by Okoye, who serves the Red Queen, Wanda Maximoff. The horde, which includes the zombies Steve Rogers,[b] Clint Barton, Ava Starr, and Emil Blonsky, storms and overwhelms the base's defenses. Though Alexei kills Rogers and Blade Knight kills Starr, Melina sacrifices herself to allow the others to escape. Blade Knight reveals that he knows of a ship capable of reaching space.

EPISODE 2
In a flashback, Xu Shang-Chi, his best friend Katy Chen, FBI officer Jimmy Woo, and a group of survivors are saved from a zombie horde by the Ten Rings organization led by Shang-Chi's father Xu Wenwu. When Shang-Chi is bitten, Wenwu bestows him with his mystical Ten Rings to contain the infection and sacrifices himself to give them time to escape. In the present after fighting off Skrull bandits, Shang-Chi, Katy, Woo, Death Dealer, and their group arrive at Helmut Zemo's sanctuary, the repurposed Raft, along with Kamala's group. The two groups agree to work together, but en route to New Asgard, Zemo attempts to sacrifice them to the infected Talokanil for safe passage. Instead, a zombie Namor leads his people to attack the Raft, killing the refugees as Zemo and John Walker attempt to flee in an escape pod. Namor kills Walker, along with most of Shang-Chi's crew, and Kamala deduces that Wanda is after the transmitter, before she kills him. When the Raft begins to sink, Yelena, against Alexei's pleas, stays behind to manually override the escape pod's launch. The group successfully escapes, while Yelena toasts her fallen allies before drowning.

EPISODE 3
In a flashback, Peter Parker, Scott Lang's head, and T'Challa arrive in Wakanda only to see it conquered by a zombie Thanos. The trio fight him alongside Thor, Rocket Raccoon, and Groot. Thanos kills Groot, Rocket, and gravely injures Thor before attempting to snap the Infinity Gauntlet. T'Challa sacrifices himself to push Thanos into Wakanda's vibranium core, destroying the Infinity Stones and releasing a surge of energy. Peter and Scott are saved by the remaining sorcerers of Kamar-Taj. In the present, Kamala and her group reach New Asgard, with Blade Knight convincing Valkyrie to let them in by way of the god Khonshu. The Asgardians have been feasting thanks to a gift from the Queen of Sokovia, Wanda herself, who reveals that she regained control of herself and is actually after Kamala's power to use with the energy surge. The food, revealed to be zombie remains, infects the Asgardians and Alexei, who then kill Zemo, Woo, and Death Dealer. The heroes flee while Thor fights Wanda, escaping in an Asgardian ship into space. They activate the transmitter, but the already stationed Nova Corps reveal that Earth has been quarantined, before attempting to kill them.

EPISODE 4
The Nova Corps shoots down the spaceship, but the heroes are rescued by the sorcerers of Kamar-Taj, who reveal that the surging energy of the Infinity Stones is being contained by "Infinity Hulk". Wanda arrives, having amassed enough zombies to defeat him and take the Infinity Stones' power for herself. Infinity Hulk initially fights off the zombies before the heroes arrive to defend him, but are soon overpowered by zombified Melina, Red Guardian, Yelena, Hope Van Dyne, Woo, Death Dealer and Thor. One by one, Sara Wolfe, London Masters, Rintrah, Valkyrie, and Blade Knight fall to the overwhelming hordes, Shang-Chi is bitten and Peter, Katy and Scott are captured. Infinity Hulk unleashes a powerful blast to defeat Thor, leaving him vulnerable and allowing Wanda to take his power. Despite her initial refusal, Kamala is persuaded by Wanda to help her remake the world. After a blinding explosion, Kamala wakes up and reunites with Riri and Kate, with things seeming to have gone back to normal. However, reality flickers, and the real Riri tells Kamala she has hacked the system, and that what she is seeing is not real.