Activate Ashnod's Altar Altar by sacrificing Inga, adding CC.
When Inga dies, it's second ability and Nim Deathmantle trigger.
Resolve the Inga trigger, causing you to draw three cards.
Activate Skirge Familiar twice by discarding two cards, adding .
Resolve the Nim Deathmantle trigger from step 2, causing you to pay 4 to return Inga from your graveyard to the battlefield, and attach Nim Deathmantle to it.
When Inga enters the battlefield, its first ability triggers, causing you to scry 3.