The Westward-Bound Survivor Group is a group of zombie apocalypse survivors who have banded together in an effort to deliver infection-immune Murphy to researchers in California. The group is comprised of individuals from all walks of humanity, many of whom carry with them the burden of a secret former life unknown to the rest of the group.
The mission is to deliver Murphy alive to the research lab in order to make a vaccine out of his blood. The mission came to an end in the season 2 finale "All Good Things Must Come to an End".
See Westward-Bound Survivor Group Vehicles for information on the vehicles the group acquires and abandons over the course of the series.