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!