After barely surviving in the jungles of Belize, The Joker's fled to Europe! Jim Gordon pursues the super-villain, but the seeds of doubt are sprouting... If The Joker didn't gas Arkham Asylum, who did? And what's the next move for Vengeance, daughter of Bane? Collecting The Joker #6-9 and The Joker 2021 Annual #1!