The Giants of Thessaly (The Argonauts)

In 1250 BC, Zeus's wrath descends upon the Kingdom of Thessaly, bringing on hoards of cruel, barbarian invaders from the East and violent volcanic eruptions from the surrounding mountainsides. Lava overflows the land and scorches the fields, leaving the populace starving and fearful.
To abate Zeus's ire, Jason, legendary hero-leader of Thessaly, quests for the Golden Fleece. As he seeks this token of the divinely favored, Jason leaves the conniving Adrasto's poisonous ambition mixed with political infighting augers civil war and vengeance from the gods unless Jason can save the threatened city. (official distributor synopsis)