Help defend the checkpoint

Help defend the checkpoint is a miscellaneous quest $$ It is available when approaching a checkpoint after completing the main questline.

Detailed walkthrough
After completing the main questline, the faction that the Sole Survivor sided with will takeover various checkpoints throughout the Commonwealth. If the Sole Survivor arrives at one of these checkpoints, they may gain the quest automatically as attackers spawn to attack the faction. The quest will end with either the attackers or defenders all dying.