This is a two-parter quest found in Oxenfurt.
Start at the Oxenfurt Harbour signpost. Wander south and you ought to find three mercenaries hassling a woman named Dora. Approach them and no matter what you say they’ll end up battling you. Try to leave your sword sheathed and take them out with your fists; if you do so you can chat with their target and escort her home.
If you return to Oxenfurt a few days later and you may be ambushed by five mercenaries in an alley. Dora leaps to your rescue. Defat the baddies together to complete the quest.
This quest is only available during night.