Fallout: New Vegas - I Am The Doctor II - Part 6

In which, having convinced the Great Khans to leave the Mojave Wasteland peacefully, we start clearing out our quest log and recruit the hard-drinking, ass-kicking Cass as a companion after buying out her caravan... leading to a quest to discover what the heck happened to her caravan and a bunch of other caravans killed by someone packing high-power weapons.