7 superheroes are invited to an island villa under false premises: Captain America, Doctor Strange, Firestar, Iceman, Namor the Sub-Mariner, Shanna the She-Devil, and Spider-Man. They soon discover that they are trapped on the island, that they have no way of contacting the outside world, and that their mysterious host is their old foe Chameleon. The master-of-disguise super-villain (who seems to be actually shape-shifting) is able to impersonate each of the present heroes (including the two women), and systematically lures them intro deadly traps. However there is a spanner in the works. Spider-Man had promised to take care of Ms. Lion, Aunt May Parker's pet dog. He has brought the dog with him to the island. While Chameleon can disguise his visual appearance and voice, he can not disguise his scent. Chameleon's seemingly perfect plan is increasingly undermined because a meddling dog can see through his disguises.
—Dimos I