The return of Etrigan! Knight of Shadows begins with a flashback to our favorite Demon?s origin. It seems as if back during the Camelot days, Jason Blood was a knight in King Arthur?s court. Seduced by Morganie Le Fay, Jason Blood betrays his master and allows Le Fay to invade Camelot. As punishment, the wizard Merlin binds Blood to the demon Etrigan.

Fast forwarding to the present, Morgaine Le Fay has returned and is searching for the Philosopher?s stone that Merlin hid from her years ago. She seeks to use the stone to bring back Camelot, so that her son Mordred can ascend to the throne. Blood senses danger and enlists the help of Batman. After their first tussle with Le Fay, Batman enlists the help of the Justice League. Etrigan reveals that Le Fay has an amulet that warns her of his presence. J?onn volunteers to use his telepathy to track down Le Fay, but he soon discovers that Le Fay?s powers dwarf his own. J?onn finds himself a victim of Le Fay?s illusions, and she has him believing that he is back on Mars with his family. Etrigan manages to pull him out.

Meanwhile, both parties track the philosopher?s stone down to two people. Flash and Wonder Woman go to invest a millionaire playboy, who looks suspiciously like Hugh Hefner. Batman, J?onn and Etrigan go to the other source, but finds that he does not have the stone. Morgaine meets them there, and in the ensuing battle, she controls J?onn and injures Batman in the process.