For centuries, angels have walked among humans and succumbed to the pleasures of the flesh. This practice has spawned the Nephilim, powerful beings who are feared by their human kin, and scorned by their angelic parents.
The angels are a race divided. The Bright Host enforce God’s will, and hunt both Nephilim and disobedient angels with equal fervor. The Dark Host, indifferent to their bastard children’s plight, bide their time in the ruins of Eden and seek to reopen Paradise to their beloved humans.
Silver, born to the angel Lorin, knows nothing of our (brutal POV shift here) world. His six-century existence has consisted of long periods locked in a stone prison, hidden from human and angel alike. He emerges only at his mother’s command, to slaughter the Nephilim. His power is limitless, yet he obeys Lorin unconditionally.
When the Bright Host mark Lorin for death, she calls on the one angel she still trusts, and confides in him the terrible secret Silver holds. Her final wish is to have her son destroyed. However, Remmael can’t bring himself to kill this seemingly innocent creature, and sets Silver free.
Released from his mother’s absolute control, Silver is thrust into an ancient conflict in which all sides believe him the solution. The Bright Host want him annihilated. The Dark Host crave his power. The Nephilim desire his allegiance. Silver must choose his own path, for he holds the power to restore Eden...or to destroy the world.
This is a synopsis, not a hook.
Focus on Silver. Don't explain everythinig. Show us his dilemma.