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. Meanwhile, Eva must face a shattering truth.
Feeling overwhelmed with all the changes since Crisis, Barry conducts an experiment that goes awry and puts him directly in Gorilla Grodd's path; Iris works with Eva to escape the Mirrorverse.
As Eva becomes more powerful, Barry and the team must find a way to stop her. They are shocked when an old friend, Sue Dearbon (recurring guest star Natalie Dreyfuss), risks her life to help.
When Joe’s life is threatened and he’s offered Witness Protection, he refuses to stop investigating Joseph Carver. Meanwhile, Iris becomes suspicious of Eva.
After recent events, Barry takes a closer look at his life with Iris. Meanwhile, Eva makes a bold move.
