When Barry suddenly gains the power of speed thinking, he attempts to use his new gift to save Iris; while Barry is thrilled with his new power, Cisco is hesitant to trust it; Eva must face a shattering truth.
Stars: Grant Gustin, Candice Patton, Danielle Panabaker
Director(s): Alexandra La Roche
Writer(s): Greg Berlanti, Andrew Kreisberg, Geoff Johns