The Vault of the Heavens is an area in the Crypt of Hearts and the final area of The Elder Scrolls Travels: Shadowkey. This is the original home of the Star Teeth before they were scattered around Tamriel.
In the final battle of Shadowkey, the Umbra' Keth must be led to the Vault of the Heavens. This is where the Star Teeth can be placed on their pedestals, so the Umbra' Keth can finally become vulnerable. The enchantment created from placing the Star Teeth on their pedestals has the power to cut through shadows, thus making the Umbra' Keth weak to it.