There's no cure for terror! Gotham is in the grip of a citywide panic attack, and only Batman can stop the Scarecrow's viral fear formula from falling into enemy hands. Meanwhile, Harley Quinn makes her ACN television debut… by taking station management hostage! New friends, new foes, and old flames collide as Bruce Wayne reclaims his cape and cowl — with a vengeance! — in the epic finale of Batman #89: Echoes.