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.
A terrorist detonates a nuclear bomb, and Flash must race between microseconds to try and stop it. Jesse and Jay lend their speed to his efforts, but even the three of them aren’t fast enough to stop a nuclear explosion that has already happened.
The team discovers the identity of the ninth bus meta, but she doesn’t want their protection. Meanwhile, Cecile turns to Harry for help when Joe’s dreams keep her awake at night.
When Wolfe offers Barry and the bus metas to Blacksmith, Barry engineers an escape for all of them. Meanwhile, Ralph has a crisis of faith when an old “friend” tells him that he eventually fails everyone who counts on him.
The team goes after a meta with the power to shrink people and objects… and Cisco and Ralph ended up reduced to two inch height. Meanwhile, Barry tries to give Big Sir hope that they can clear his name.
While Barry sits in prison, Ralph faces his first major supervillain and is injured for the first time. He has second thoughts about being a hero, and turns to Barry for advice.