AllMovie

In the conclusion of a two-part story, an evil alien spirit continues to wage war against mankind via the Black Heart, a powerful lunar gemstone. The stone has cast its sinister spell on virtually every member of the Justice League, transforming them from heroes to villains. Only The Flash has managed to escape the Black Heart's influence -- and it is up to him to set things right before the alien baddie can create a solar eclipse that will destroy both the sun and the Earth.