A strange craft is seen moving at the speed of light and digs its way to Central City Park.

When Barry Allen's friend, stage actor Fred Pearson (and star of the show The Great Gorilla) fears that he may be the strange gorilla creature that stalks the city at night, he calls Barry for help.

As Barry leaves the police station to meet Fred, he bolts through the park where he spots another unidentified object moving at the same speed the Flash does. He catches up to see a ship that suddenly reverses directions. Flash takes too long to turn around and loses it in the park. Flash decides he better hurry to meet Fred as he had originally planned.

At dinner, Fred tells Barry how he had been knocked out before his performance the previous evening. However, when he woke up, he found out someone else gave a performance that went over well with the audience. All Fred can remember is voices in his head saying they "needed to hide for a bit".

At Central City Park, the craft reappears and Gorilla Grodd reveals he came from a hidden city in Africa. He has come seeking the world's greatest mind so that he may learn the secret of mind-control. He wants to use it to control the armies of Gorilla City in order to take over the world.

Grodd finds Solovar, a member of his own race, who has let himself be captured by humans and put in a zoo. Here he has posed as an ordinary ape in order to keep Gorilla City a secret from the world of humans. Stealing the ability, Force of Mind, Grodd returns to Gorilla City to begin his plans of domination.

Solovar frees himself and seeks out the Flash and asks for his help in stopping Grodd. The two travel to Gorilla City where Grodd has just taken over the army. Flash manages to battle Grodd by spinning around him faster than Grodd can think. This knocks Grodd out and removes the knowledge of Force of Mind from his memories. Flash then turns Grodd over to Solovar for punishment, and promises not to reveal the secret of Gorilla City's location to the rest of the world.

Returning to Central City, as Barry, the Flash tells his friend Fred that he need not worry about the strange gorilla sightings anymore, and then takes Iris out on a date to the zoo.

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