Team Flash track down the final bus meta Edwin Gauss, but are followed by the Samuroid, who injures Caitlin. The team rush back to Star Labs to regroup and heal. Caitlin reveals to Iris that Killer Frost is activated by her adrenal gland, and she is working on a way to separate them. Harry comes up with a tuning fork weapon that mimics Izzy's abilities in order to defeat DeVoe. Ralph reveals to Barry that he isn't afraid of losing his own life, but of Team Flash losing theirs, as he considers them family. Wells is shown to be addicted to the Thinking Cap, which Joe helps him deal with. Ralph takes the fork, with the intent to go with Edwin to kill DeVoe, which Barry argues against. Eventually, DeVoe manages to take over Edwin's mind, and as well takes the abilities of Janet Petty and Matthew Kim, before transferring his mind into Ralph's body. The team try to stop him, but DeVoe incapacitates them, and seemingly removes Killer Frost from Caitlin before leaving. Back at the lair, DeVoe uses Ralph's morphing abilities to morph back into his original form, while he and the Mechanic plan their next move to destroy Team Flash.