DeVoe infiltrates the A.R.G.U.S. facility holding Fallout by impersonating John Diggle and kills most of the security, except for a few hostages; overcharging and killing Fallout to be a nuclear battery for the satellites. Barry runs to Star City and brings back John to reveal the location of the facility. Caitlin and Cisco ask Barry to train them in Flashtime so that they can save the hostages and Barry can follow DeVoe through the breach before it closes. In the last stages of pregnancy, Cecile's telepathy causes her to take on the personality and thoughts of anyone nearby. Harry and Iris track Marlize to London, and use the last extrapolator to get there. Caitlin and Cisco are able to rescue the hostages. Searching her mind for Killer Frost, Catlin has Cisco vibe her into a repressed memory of a childhood accident; Killer Frost was already part of Caitlin decades before the particle accelerator had created any metas. Barry manages to follow DeVoe through the breach and destroys one of the satellites with Amunet's bomb. DeVoe takes control of S.T.A.R. Labs and uses its satellite to replace the one destroyed. He initiates the Enlightenment protocol in the time vault.