"In Lonesome Road you are contacted by the original Courier Six, a man by the name of Ulysses who refused to deliver the Platinum Chip at the start of Fallout: New Vegas. Ulysses promises the answer as to why he didn’t take the job, but only if you make one last journey into the hurricane-swept canyons of the Divide, a landscape torn apart by earthquakes and violent storms. It’s up to you whether you take the job or not."
Ulysses offers the Courier a job that leads him to the Divide. But the question is - what is this "job"? Could it have to do with the Courier helping Ulysses, or not? Could it be a courier related job with a package? Either way, we know we will have to fight him. Well... time to speculate!