There's a new supervillain in town, and his name is The Ace. Gathering together a gang of four hardened delinquents, the Ace decks them out in sinister playing-card costumes, and thus the Royal Flush Gang is born. In their efforts to defeat this scurrilous quintet of no-goods, Robin and Cyborg discover that the Ace is taking his orders directly from their perennial enemy Darkseid—while Robin's sidekick Batman learns to his astonishment that the Ace is not a "new" nemesis at all, but instead a very old one... The Joker!