This quest becomes available after completing Count Reuven's Treasure and A Matter of Life and Death.
Meet Triss at her Hideout and she will ask you to help her smuggle mages out of Novigrad. The only problem is there are two mages who are in trouble so you have a choice to make. Any conversation option at this point asking Triss to worry only about herself will not end well for Geralt. You can't save everyone but this is the only time Triss will let Geralt make a decision for her during this quest.
1. Save the two mages: You'll need to follow Triss to the couple's safe house. You'll fight the gaurds outside of Triss's hideout but avoid combat before getting to your destination by hiding behind corners when Triss does. You'll need to use Axii on one of the mages to get them to come with you. Even if you save the mages someone will die. When you get to Oliver's there will be witch hunters there you'll have to fight and afterwards you'll find Oliver dead on the ground.
GAMER TIP: Kill the witch hunters fast as they can still kill the two mages once you get there.
2. Leave the Mages: The mages are left for dead and you sneak off to Oliver's.
Once you reunite with the rest of the mages Triss is helping escape you'll have to clear the tunnels leading to the dock. You will encounter drowners, rats, and a katakan vampire.
|Katakan||- Moon Dust or Devil's Pufball Bomb|
- Vampire Oil
Once you reach the docks and defeat the last of the witch hunters you'll have one final chance to get Triss to stay.
|REQUIREMENTS FOR TRISS TO STAY|
|1. Kiss her during A Matter of Life or Death|
|2. Say "I love you" at the docks|
|3. At the start of Now or Never do not tell her you do not want to help the mages. I'd recommend avoiding all secondary conversations altogether.|
|4. If she stays DO NOT say she is changeable|
If you meet all the requirements than Triss will comeback and you can watch the shi leave from the lighthouse. Geralt and Triss share a lovely moment discussing their future before sealing the deal.
GAMER NOTE: Dijkstra will want to talk to you about Phillipa Eilhart on the docks, let him.
For more tips on romancing the ladies in Witcher 3 refer to our Sex & Romance Guide.