Barry Allen had his most challenging battle in "The Flash" Season 2 Episode 6.
"The Flash" Season 2 Episode 6 is entitled "Enter Zoom." According to Melty, Episode 6 saw Allen in an ongoing heated battle with Dr. Light, who managed to take down the Justice League speedster. Dr. Light took his new flash emblem from his chest and said "Zoom always wins."
Episode 6 also saw Dr. Light get out of her containment cell, after Allen hoped that she would be their alliance in stopping Zoom. Linda Park, Dr. Light's Earth-1 counterpart, said that she agreed to assist the team by imitating Dr. Light.
Dr. Wells also created a speed reducing serum while the team simulated a battle at one of the breaches in order to trick Zoom through; however, the team failed, since Zoom knew that it was a trap. As a result, he went after Park prior to facing Allen.
Being much faster than Allen, Zoom managed to knock him out. The Flash's body was then shown in the local news and the police station, prior to going back to the S.T.A.R. Labs. Zoom stabbed Allen with his hand; however, Cisco shot him with the serum. Zoom was hit, but he had enough speed to escape.
Episode 6 also saw Dr. Wells reveal that Zoom had his daughter Jesse and he had come to Earth-1 to stop the evil speedster. Then, Allen woke up from his injuries and learned that he could not feel his legs.
Meanwhile, Gorilla Grodd is set to return to Central City in "The Flash" Season 2 Episode 7, which is entitled "Gorilla Warfare." According to Spoilers Guide, Grodd would go back to Central City and would abduct Caitlin.
Allen and the team went on to find her before it was too late. Cisco would also plan his first date with Kendra Saunders, the new barista at Jitters. Then, Patty would suspect that Allen was hiding something from her.
"The Flash" Season 2 Episode 6, "Enter Zoom," aired on Nov. 10 while Episode 7, "Gorilla Warfare," airs on Nov. 17.