Although this quest in The Witcher 3 is steeped in espionage and linked to other quests revolving around spies and politics, "A Deadly Plot" is undeniably more of a hostage rescue scenario. This secondary quest can be started by having a conversation with Dijkstra at the end of the quest "Now or Never". Be sure not to start "The Isle of Mists" main quest, as that will cause this one to fail.
After A Deadly Plot has been started, the player will receive a quest marker on their map that will guide them to the decadent brothel known as the Passiflora. When inside, speak to Marquise Serenity, the Madame of the brothel, and she will lead Geralt to a hidden room up the stairs where he will encounter Dijkstra and Vernon Roche, with who he will discuss the matter of a missing contact.
This quest is pretty straightforward, however, here's a list of the more important parts to help one keep track of everything.
Main Objectives
- Head to the Passiflora to meet up with Dijkstra & Roche
- Meet with Gregor at Border Post for intel
- Follow the intel to the site of an abandoned wagon
- Fight off the wolves here & search for tracks
- Follow tracks until one encounters a rock troll
- Talk to the troll to learn that they have taken the contact hostage in a nearby cave
- Enter the cave and confront the trolls
- Fight OR talk with the trolls to rescue the contact
- Escort the contact back to their wagon to end the quest
- Play Gwent with the contact (optional)
After the briefing with Dijkstra and Roche, the quest will update and indicate where the next lead about Dijkstra's missing contact can be found. The player must head to Border Post, located on Halver Isle, to speak with another of Dijkstra's allies: a Redanian soldier named Gregor. Upon reaching Border Post and chatting with Gregor, the man will indicate that Geralt can learn more by tracking down the wagon of the contact who was posing as a shoemaker riding around with a unique wagon.
This wagon can be found by heading southeast from Border Post and is north of the Hanged Man's Tree fast travel sign. It will be just off to the side of the road, though has not been damaged or attacked by the look of it. While examining the scene, some wolves and a warg will attack. There aren't many of them, so dispatch the beasts with swift swordplay and the Igni sign before continuing one's investigation.
Use one's witcher senses to find some tracks before following them. This will lead Geralt to a lone rock troll named Rogg surrounded by many shoes, which brands them as the most obvious of suspects. Speaking with the troll will reveal that they and their 2 brutish buddies, Ogg and Pogg, have kidnapped the contact and are holding him hostage in their nearby cave. Head to this cavern, which is very close to where Rogg stands, and confront the rock trolls on their turf.
Rescue The Contact From The Rock Trolls
After entering the cave and delving deep enough into it, Geralt will come across Ogg and Pogg along with the contact, who turns out to be the fence Thaler; an old acquaintance of Geralt's that players may recognize from previous games in The Witcher series. Players can choose to either speak with the trolls or fight them after the cutscene plays out, however, it is recommended to fight the rock trolls so that one can harvest their precious and rare livers to use as potion ingredients.
The fight will be quite tricky, as not only will Ogg and Pogg alternate between aggressive melee attacks and throwing stones, but Rogg will show up very shortly after the fight begins as well, making this a 3-on-1 fight since Thaler is too much of a wimp to help out. The battle will be a chaotic mess of flying rocks and brutal punching, which will give the player little time to dodge and counterattack, however, liberal use of the Quen sign can prevent one from sustaining too much damage from the numerous assaults. Applying Ogroid Oil, preferably the Superior version, can make this fight go by more quickly and help the witcher to cleave through the trolls' tough hides.
Escort Thaler Back To His Wagon & End The Quest
The manner in which one deals with the rock trolls has no impact on the quest, therefore either method is acceptable to progress onward. After rescuing Thaler from their clutches, one way or another, Geralt will have to escort the contact back to his wagon.
Unfortunately, Thaler is a very slow walker, so the player will have to march next to him as they backtrack to the cart laden with shoes. This will at least give one the option to chat with Thaler along the way, which provides something to alleviate the otherwise boring trek thanks to Thaler's interesting, and sometimes vulgar, dialogue.
After reaching the wagon, speak to Thaler to wrap up any conversational loose ends and the quest will complete. Don't take off just yet, though, as the player can potentially play Thaler in Gwent and win one of his prized cards, however, this will require the player to have completed a few other quests in the Gwent-related group. If one does not have the option to face off against Thaler, fear not, as he can be found later at the Seven Cats Inn and will accept a card game there.