Clark's old friend Bart Allen returns to the series with a new look but carrying a terrible secret. Mysterious "speed storms" break out across the globe, possibly related to Bart's demons. Racing to find answers, Superman and Impulse confront a reluctant ally: the JSA's Jay Garrick. Meanwhile, as Lex hands Tess an ultimatum to reveal everything she knows about Superman or face oblivion, Lois' investigation into him takes a surprising turn. And Chloe's journey through her doppelgänger's memories to reveal her secret turns dangerous.