When Bruce Banner takes his lab team to Jotunheim, that means only one thing: Hulk vs. Frost Giants! Thor joins the fray, but what's wrong with the God of Thunder - and why doesn't he recognise Hulk? As the Frost Giants prepare to invade Earth, not even Hulk and Thor can stand in their way - so they'll have to call in some help! Plus, the secret of the Portal to Jotunheim is revealed, as Bruce Banner lands a bombshell surprise on his assistants!