Cold, Cold Heart

 is a quest in Fallout: New Vegas.

Quick walkthrough
Talk to Vulpes Inculta in Nipton then walk to Sgt. Kilborn at the Mojave Outpost to "spread the word".

Detailed walkthrough
When you arrive in Nipton, you will encounter a man who won the lottery. Go into town and you will confront Ceaser's Legion. Go to the Mojave Outpost, and speak to Sgt. Kilborn about the attack. Then you will complete the quest.