As Wallace and Avery race to uncover the mystery of the missing S.T.A.R. Labs scientists, something appears to be affecting their friends–is it tied to the bubbles popping up all over Keystone, or the spooky Speed Force stuff Mr. Terrific is warning everyone about? Also, a classic Flash character appears–and is really into EDM, but to what end? The young Speedster team-up continues!
