The Unforgiven

The Unforgiven is the main quest that closes Act III of The Witcher in Vizima’s Trade Quarter. Triss hands it over at the end of Lock and Key and sends Geralt to Leuvaarden, who is blunt about it: beating Salamandra takes an army. Velerad will not commit the city guard, which leaves two real options, Yaevinn’s Scoia’tael or Siegfried and the Order of the Flaming Rose, and Geralt must stick with whichever side he backed in Gold Rush.

The plan unravels at the New Narakort, where a Salamandra trap springs and Count de Wett shows up with the king’s men. Triss teleports Geralt straight into the gang’s last base, where he opens Alvaro’s portal for his allies and goes after the Professor and Azar Javed. Azar slips away; the Professor meets a messy end at the hands of a kikimore queen, and notes found in her lair reveal that Princess Adda forged royal edicts and was helping Salamandra all along.

Walkthrough

After Lock and Key, talk to Triss, then to Leuvaarden about raising an army.
Recruit the faction you sided with in Gold Rush: Siegfried at the Order’s cloister or Yaevinn at Vivaldi’s house, both in the Temple Quarter.
Tell Triss (she will only talk once The Source is done). She sets up a meeting at the New Narakort. Wrap up any open Act III business first: entering the inn pushes you toward Act IV.
Survive the fight at the inn, where your Vincent Meis choice decides whether he fights against you, with you as a man, or with you as a werewolf.
When de Wett arrives upstairs, Triss teleports you to the Salamandra base. Clear the roots with Aard, fight through and meet your ally.
Activate Alvaro’s portal with a power stone (from Lock and Key or from the Salamandra mage in the alcove, which also holds a Circle of Waning Magic that boosts Yrden and a sun rune in a crate).
When the army arrives, chase the Professor to his laboratory, cut down his guards and kikimores, and fight him one-on-one.
After the floor collapses, run from the kikimore queen (she kills in one hit), stand in the western tunnel and Aard the support beams to bury her.
Loot the queen, including the Professor’s report, then leave the lair; Princess Adda’s men are waiting and Triss teleports you to Lakeside for Act IV. Save before leaving.

Quest Consequences & Choices

Allies: you must pick the same faction as in Gold Rush; asking the other side offends them.
Vincent Meis: killed in Lock and Key, his men fight you at the inn; spared, he fights at your side, human if cured or as a werewolf if not.
Whichever way it goes, Salamandra loses its Vizima base, the Professor dies and Azar Javed escapes.