Archon of Falling Stars and Viscera Seer on the battlefield.
Steps
Activate Viscera Seer by sacrificing Archon of Falling Stars.
When Archon of Falling Stars dies, it triggers, returning Necromancy from your graveyard to the battlefield.
When Necromancy enters the battlefield, it triggers, returning Archon of Falling Stars from your graveyard to the battlefield, and attaching Necromancy to it.
Resolve the Viscera Seer ability, causing you to scry 1.