Calvin Zabo, an employee fired by Donald Blake for stealing, vows revenge and uses a chemical formula to turn himself into the super powered Mr. Hyde.

Thor's nemesis Loki forges an alliance with supervillains Mr Hyde and the Cobra. The trio kidnap Jane Foster to lure Thor into a booby-trap.

Zarrko, the Tomorrow Man, travels back in time to 1962 to steal a cobalt bomb that he plans on using to make himself ruler of the 23rd century. Thor follows him forward to 2262 in order to defeat him.