A simple task turns to a catastrophe when a radioactive block accidentally falls into the lava river and produces mutant creatures.
Morgan, Tom, Nora, and Paul are to deliver 12 radioactive Copper blocks to Frank Bones in exchange for getting the equipment needed to find a cure for their Strider friend and humans who have fallen ill due to radiation exposure. Unfortunately, one of the radioactive blocks they were carrying falls to the lava. They cannot retrieve the blocks because mutant Hoglins and Magma Cubes keep on attacking them.
Frank Bones is not pleased that one of his precious blocks is missing. The deal is off. He will not lend the equipment to them with an incomplete delivery but proposes that he will send an army to the Nether to help Morgan and his friends retrieve the blocks.
Will the Striders and Paul finally get the block from the lava with an infantry to back them up? Or have the mutant creatures evolved into creepier and fiercer monsters that the army cannot beat? Will a cure ever be produced for those who have fallen ill due to radiation?