You will only need to complete this mission if you accepted Zoltan’s and Iorveth’s proposal in the quest At A Crossroads: Scoia’tael. Otherwise, you will be running an assassination mission for Roche.
Once you accept the proposal, head into the forest where you initially found Iorveth and fought his Arachas. The Scoia’tael will be waiting for you here. This quest can go one of two ways, depending on whether or not Iorveth is free in your game. If he is still a free elf, he will accompany you on the mission. Iorveth will suggest assaulting the ship from the shore before boarding it to finish the job. You can suggest an alternate plan to sneak onboard in which you’ll pretend that you’ve taken Iorveth prisoner. If, however, Iorveth is currently in the prison, you won’t be able to suggest the alternate route and will be forced into attacking the ship.
If you take the sneaky route:
Accompany Iorveth to the prison ship, located at the end of the pier. As you walk him onboard, a guard will smack him and you can react using persuade, intimidate, or Axii. Your decision here has no real affect on the rest of the mission. As soon as you get onboard, free Iorveth and waste no time attacking the guards. Killing all of the guards on the main deck will initiate a cutscene in which Loredo sets fire to a tower full of elves hoping to distract you from your plot. This leads to yet another branching path; you can either save the elves or chase down Loredo.
If you decide to save the elves, waste no time in running to
the base of the tower. A few angry guards will try to impede you, but they are
easily dealt with. Quickly climb the ladders to the top and click the left
mouse to free the three elves. Jump out of the window into the sea, where
Iorveth will rescue you. If you save the elves, one of them will reward you
later in Act II.
If you decide to kill Loredo instead, chase him to the gallows. A group of three soldiers will emerge to intercept you along the way, but they have low health and can be killed quickly. After cornering Loredo by the gallows, you’ll have to fight him. He will enlist the help of one soldier. Kill the soldier first, as he will be the easiest target, then focus on Loredo. He wields a halberd, which has a dangerously long reach. Loredo is best dealt with by using a similar tactic to the one you’d use when fighting shielded soldiers. It’s best not to attack from the front, so roll around and deal a series of fast blows to his back. After killing him, head to the docks below the burning tower and take one of the small boats out to see Iorveth. No matter which decision you made, Iorveth will be pretty satisfied with the results. Confident from his recent victory, Iorveth will tell you that if he encounters Roche again he will slay him in battle. You’ll receive 1,750 experience points and set sail for Aedirn.
If you attack the ship:
Your attack party will split into two. Geralt will head to the cliffs near where you originally docked in Flotsam. Along the way you’ll encounter three soldiers, who should be defeated easily. Upon reaching the cliffs you’ll see a Blue Stripes ship sailing away from Flotsam. Once you reach the top of the cliff, you’ll see a lot of activity going on near the prison ship. Soldiers will be moving to attack it. If Iorveth was captured earlier, he’ll be tied up and you will have to set him free. Otherwise, he will have already started his attack on the ship. Either way, run down towards the ship to help him.
Numerous soldiers stand in your way. The large, shirtless soldiers are tougher to kill than the smaller, relatively weak ones. Stay nimble and use light attacks to kill each of the weaker soldiers. Feel free to use heavier blows when bringing down their larger, slower companions. After you board the ship, help Iorveth out and mop up the stragglers. Upon clearing the deck, a cutscene will initiate showing Loredo fleeing as he sets fire to a tower full of elves.
This section plays out similarly no matter which plan of attack you went with. You can either save the elves or kill Loredo, but not both. If you wish to save the elves, head over to the base of the tower and take out the guards. Use the ladders to scale the tower quickly, and then left click to free the three shackled prisoners. Finally, jump through the window to land safely in the sea. Helping the elves will earn you a reward later in Act II.
If you decide to kill Loredo instead, chase him to the gallows. Three weaker soldiers will emerge to block your path on the way, but they have small health bars and can be killed very easily. Once you corner Loredo, he’ll call in backup from another soldier and attack using a halberd. Kill Loredo’s companion soldier first, as he can become annoying if not dealt with early. Once you’ve taken care of his guard, you can dodge around Loredo’s attacks and hit him from behind to kill him. Go back to the burning tower and take one of the ships there to meet Iorveth at sea. You’ll talk to him about Roche and earn 1,750 experience points.
No matter which decision you made during this quest, this will mark the end of Act I.