Spoilers Ahead! The Flashpoint Paradox

While visiting his mother's grave, Barry Allen, known as the Flash, is alerted to a break-in by his Rogues (worst enemies) at the Flash Muesum. Defeating the Rogues, he discovers that they have been hired by his archenemy Reverse-Flash as part of a plan to destroy Central City. With the help of the Justice League, Barry foils Zoom's plot, but Zoom's taunts over the death of his mother still haunt Barry as he departs.
The next day, Barry discovers that the world has radically changed: his powers are gone, his mother is alive, and the Justice League does not exist. Aquaman and his Atlantean forces have sunk most of Europe, while Wonder Woman has led the Amazons in conquering the United Kingdom, and both forces are now at war. Cyborg has assembled a team to eliminate both parties and approaches a version of Batman who does kill to join them, but his refusal leads the government to scrap the plan.
Barry visits Wayne Manor, but is attacked by Batman—who he realizes is not Bruce Wayne but his father Thomas Wayne. Attempting to explain things to the elder Wayne, Barry retrieves his costume from his ring, but a Reverse-Flash costume appears, causing Barry to believe Thawne is responsible for the timeline alteration. Barry convinces Batman to help, and Batman helps him recreate the accident that gave him his powers, but Barry is severely burned.
At the Batcave, after realizing that his memories are changing, Barry asks Batman to recreate the accident again. The second attempt results in success and Barry's powers are restored and he alters Professor Zoom's costume to match his own. Testing his speed he discovers he cannot travel through time because Zoom is also using the Speed Force (the fuel for super speed). Barry recruits more allies, beginning with Superman, who is a prisoner of the U.S. government after his ship crashed into Metropolis. With the aid of Batman and Cyborg, they liberate Superman, who is empowered by Earth's yellow sun for the first time, then flies off in fear and confusion. Barry collapses as his memories continue to change.
Barry convinces the superheroes to help stop the war and they depart for Britain aboard Batman's jet, only to be shot down upon arrival. Batson and his siblings combine into Captain Thunder to fight Wonder Woman, while Barry, Cyborg and Batman occupy Aquaman. While Batman is wounded, Thawne reveals himself and explains that Barry is responsible for this alternate timeline: Barry traveled back in time to save his mother, fracturing the fabric of reality. Superman arrives but cannot save Cyborg from Aquaman, who then remotely detonates a radiation powered bomb after being defeated by Wonder Woman. As the explosion tears across the landscape, Zoom mocks Barry but is shot through the head by Batman. Barry races back in time and stops his earlier self but again fractures time, creating another alternate timeline.
Barry awakens at his desk and finds that reality is apparently back to normal. After spending a moment with Iris at his mother's grave, Barry visits Bruce Wayne to tell him about everything that occurred. 

All in all, a very entertaining DC animated movie. The only real problem I had was with the animation style. Many characters looked ugly and nearly identical. But besides that, no real issues worth mentioning.