There are ten events to complete, and two generic event types.
Blue missions are Jiang Shi exterminations and end with a Peachwood Sword as a reward. For Rescue the Civilian, you need to defeat a handful of Jiang Shi. For Destroy the Power Source, you need to throw the Jiang Shi in. If you try to grab them while the power source is active, they'll immediately counter with a bite, which is handy if you need to work on the Hard to Get stat award.
Purple missions are Yaoguai, so take the sword to both make it easier and contribute to the Demonic Exorcism stat award required for a separate achievement.
All secondary content will be available after completing the Ghosts of the Past mission.