A pair of humongous otherworldly creatures living in the far future. One is a rocky giant, almost mountain-sized and carved into the shape of a man. The other, avian with a body chemistry that is a more glass-like derivation of the silicon mineral that determined their name. This one is all angles and planes resembling a winged raptor.
At some point in the future, they travel to Earth where the two are overtaken by a harmonic madness which leads them to battle one another. The devastation is catastrophic, causing destruction on a planet wide scale. During one skirmish, the rock-like creature hurtles Mount Kirby into space. A seemingly minor action on his part, but it sends the mountainous mass into orbit. It will later become Asteroid K.
The Silver Agent, alongside humans of this time period, manage to find a unique piece of technology that cures the two Silicoids of their madness. They resume their cosmic journey. Their memory of earth becomes a fading nightmare.