After being defeated in combat by his half-sister Hela, Thor ends up as an imprisoned gladiator on a distant world ruled by the Grandmaster in this hugely entertaining comic-book adventure. Now, he must work together with fellow Avenger the Hulk, another combatant fighting for the Grandmaster's pleasure, in order to escape and return to Asgard before Hela can unleash the world-ending event known as Ragnarok.