Iris accidentally takes Barry's speed when a new meta with the power to swap powers touches both of them. Now they have to learn how the other half lives as Iris takes to the field and Barry monitors events. Meanwhile, Ralph refuses to leave S.T.A.R. Labs for fear that Clifford will kill him, and Harry undertakes a dangerous experiment to match their opponent's augmented intellect.

Team Flash tracks down the last bus meta, Edwin Guass, and discover that he holds the key to defeating Thinker. Meanwhile, Ralph considers taking extreme measures against Thinker,