1

The Patron has a dark secret/ulterior motives

2

 The patron has been abducted

3

 A hostile group invades the area

4

 The patron's information is wrong

5

 A person in a position of power intervenes in the mission

6

 A natural disaster strikes the region

7

 The patron hired other characters without the PCs knowing so

8

 A rival group of NPCs are after the same goal

9

 Stalked by a dangerous beast

10

 A bounty has been placed on the head of one of the PCs

11

A mysterious new player offers to pay the PCs to abandon their mission

12

 An agent of the Clan or Sect is involved in the mission somehow

13

 An unexpected alliance is required

14

 Unwanted attention from criminal group

15

 Someone in extreme need asks the PCs for help

16

 A PC suffers from a sudden, mysterious illness

17

 The PCs cross a Threshold and find themselves in a random Region

18

Ambushed

19

 PCs wrongly accused of a crime

20

 The patron has been killed and there's no reward