The Well of Ascension Book Two of Mistborn

They did the impossible, ending the thousand-year reign of the godlike Lord Ruler. Now Vin, the former street urchin turned powerful Mistborn, and Elend Venture, the idealistic young nobleman who loves her, must build a healthy new society in the ashes of an empire.

As tensions grow in the wake of the uprising, an ancient legend seems to offer a glimmer of hope. But even if it really exists, no one knows where to find the Well of Ascension or what manner of power it bestows.

It may just be that killing the Lord Ruler was the easy part. Surviving the aftermath of his fall is going to be the real challenge.