The Hulk [Bruce Banner]; Rick Jones; The Ringmaster (introduction); the Circus of Crime (introduction); Polly Jones [Rick's Aunt] (introduction, cameo); General Thunderbolt Ross; Hercules (circus strongman); Bruto; Teena
Rick takes a break from his Hulk-sitting duties and goes to the circus; Unfortunately, he picks one run by a hypnotic criminal who mesmerizes his audience and then robs them; When the Hulk arrives to bail out his buddy, he is captured and made part of the act thanks to the fact that Rick is in thrall and cannot give him any commands; Rick returns with the FBI and the Hulk finds himself free to kick some circus tail.
An alien ambassador lands on Earth and, because of its monstrous appearance, is driven away. It drops a note written in English before fleeing welcoming Earth to the brotherhood of planets and offering to abolish war, disease and poverty as benefits of membership in the galactic order.
Avengers [Thor [Thor Odinson, Don Blake]; Iron Man [Tony Stark]; Ant-Man [Henry Pym]; The Wasp [Janet Van Dyne]; Hulk [Bruce Banner, Mechano]] (introduction, origin); circus ringmaster; lion tamer; trapeze artists; Bobby; Bobby's mother; Charlie; Captain; Jane Foster; Asgardians [Odin]; Teen Brigade [Rick Jones; William "Willie" Bishop]; Fantastic Four [Mr. Fantastic [Reed Richards]; Invisible Girl [Sue Storm]; The Thing [Ben Grimm]; The Human Torch [Johnny Storm]]; Loki [Loki Laufeyson]; Silent Ones
Iron Man, the Hulk, Ant-Man, the Wasp, and Thor join forces to defeat Loki.