Reverse-Flash manipulates the Speed Force to put The Flash into a time loop, which forces him to re-live the same day over and over again. The Flash must find a way to restore time and finally apprehend his worst enemy before all is lost.
The morning sun shines on the jewel of the Metropolis skyline, The Daily Planet building. But when The Joker decides this building needs a renovation, it's time to sound the Trouble Alert because all bricks are about to break loose! The Justice League leaps into action but as the battle is brewing against The Joker something goes haywire with The Flash's powers causing him to get caught in a repeating time loop and even stranger is the yellow clad Reverse Flash taunting him at every turn! It will take all of Flash's speed, a little magic and the helping hands and paws of the Justice League's new recruits The Atom, Krypto the Super Dog and Ace the Bat Hound to break the cycle and save Metropolis!
The second Atom is introduced into the Justice League as the Joker poisons Metropolis with his Joker gas and remodels the Daily Planet. Flash arrives late after stopping for food and catching Captain Cold and Captain Boomerang. The Justice League is upset with his impulsive decisions when a yellow, vibrating speedster taunts Flash for his inferior speed. Following a chase, Flash wakes up his bed the next day; after recognizing the events from the previous day, Flash realizes he traveled back in time to the morning of that day and is able to stop the Joker. The yellow speedster taunts the Flash again and the Flash enters a time loop, repeatedly chasing the speedster and stopping the crimes of that day. Batman gives Flash advice on how to stop it, but the yellow speedster gives Flash the chase again. In a dimensional gateway, Flash pushes his power past its maximum to overtake the speedster and break the loop.
In Central City, Flash's powers are gone and the city has turned against him. Batman removes him from the Justice League after being framed for pulling pranks on the League. The yellow speedster reveals himself as the Reverse Flash-envious of Flash's fame, Reverse Flash traveled from the future to steal his (and the Justice League's) fame. In atomic size, Atom hears everything, though as Reverse Flash restrains Flash, his suit short circuits preventing him from unshrinking. Atom frees Flash and phones Doctor Fate to help Flash regain his powers. Flash is teleported to Doctor Fate and Atom attempts returning to the Hall of Justice to explain Reverse Flash's plan to the League. Reverse Flash commits acts of heroism at a rate quicker than the Justice League, gaining him popularity with the public and leading the Justice League to announce their retirement.
Flash is introduced to Doctor Fate and his assistant Zatanna. After Flash explains his predicament, Doctor Fate explains the Speed Force and reveals that Flash broke his connection to it. Doctor Fate and Zatanna send Flash into the Speed Force, where he will complete various trials to prove his worthiness of his powers. Flash completes the trials and finds the Speed Force Nexus, the primary source of power in the Speed Force. Reverse Flash arrives, having planned for Flash to complete the trials so he could acquire the Nexus without doing them himself, and places the Nexus into his suit, exponentially increasing his powers. Flash is left trapped in the Speed Force.
With the Speed Force Nexus, Reverse Flash encases the Hall of Justice in a statue of himself, made of bricks from the Speed Force that are impervious to their powers. Atom, with the help of Ace the Bat-Hound, Krypto and the Green Lantern B'dg, repairs his suit and helps the League escape to the Batcave. Flash returns from the Speed Force by creating a vehicle out of the same Speed Force bricks.
Reverse Flash builds more statues of himself and declares himself the ruler of Earth. He threatens those that disobey him will meet the same fate as the Justice League. The League, using bricks Flash brought from the Speed Force, rivals Reverse Flash's speed and destroys his statues as a distraction so Flash can steal the Speed Force Nexus from him. Flash regains his powers, with greater speed than Reverse Flash. Flash taunts Reverse Flash into exceeding the maximum of his powers; depowered, Reverse Flash is arrested by the League at the Hall of Justice. Flash takes him to prison and returns the Nexus to the Speed Force before being reinstated into the Justice League.
Flash is grateful for the restoration of his powers and the Justice League's advice. The Justice League celebrate their victory as Doctor Fate overlooks everything.
