With Barry (Grant Gustin) gone, the team must figure out a way to handle the return of an old enemy – Girder (guest star Greg Finley). Realizing Girder is retracing his steps from his last attack, Iris (Candice Patton) volunteers to act as bait to trap him in S.T.A.R. Labs. Meanwhile, Barry fights to return to his old life. Kevin Smith directed the episode written by Zack Stentz (#221).