"The Destiny Machine"
It appears that Nathan Ellery is not dead. He has been resurrected by the Conclave and is working to help them in their plans for world domination. Now that Abby and Matt have stumbled upon Ellery's lair, just like Jefferson Bolt did, they will join him in death once they have told Ellery everything they know. Their only hope is that the Swamp Thing can find and save them, which is harder than it seems now than Ellery has his advanced robotic army trying to eliminate the creature. *Source: DocRx8482