Darkseid has Jean Loring brought to him and tells Eclipso about his true origin. Eclipso sets out to bring back together the Heart of Darkness shards to make himself powerful enough to reign over the earth and to possibly possess Darkseid. Eclipso seeks a new host that's stronger, eventually being drawn back to his old host Bruce Gordon.
The Spectre seeks out to prevent the destruction that will be brought about by Eclipso. But the Spectre is limited in what he can do and endows his human host, Crisipis Allen with his own godly powers to help prevent Eclipso's wrath.
Eclipso sets out by finding super being like Plastic Man and The Creeper and so on to find the shards and reconstruct his stone. Bruce Gordon while paired with Eclipso gains some control over the shard in his possession and is able to fight off Eclipso to some degree so that he can control his powers.
Bruce soon loses control of the shard but not before having tinkered a way to free Plastic Man and Creeper and Dove from Eclipso's control. The Spectre comes back in full force to fight Eclipso after he's acquired his full power before Gordon is able to beat him of his possession once again. In the end Eclipso is stopped, but for how long?
Eclipso: Music of the Spheres