The quest starts right where the previous one ends. As soon as you reach Toussaint Geralt will receive an exciting welcome party prepared by Guillaume de Launfal and his new best friend Golyat. Obviously Geralt will step in and fight Golyat.
Note: If you manage to shoot Golyat in the eye with your crossbow it will result in an instant death and you will receive the David and Golyat achievement. However, even if you already have it you can still use this method to kill him unless regular combat is easier to you.
Regardless, after Golyat is dead you will have a short conversation on how to proceed.
To Corvo Bianco
Follow Milton the Inn, once there use your witcher senses to investigate. After searching underwater you will find a Handkerchief monogrammed "d.l.C.", now talk to Milton and you will go to the Inn to get more details. After getting all your answers it's time to go to Corvo Bianco. The place isn't far so you can go on foot. When you get close you will hear the sounds of battle, if you investigate the area thoroughly Geralt will deduct the culprit is a Bruxa and you will have the optional objective to check your journal for more info. Now enter the cellar and find the vampire, once you do Geralt will try to converse with her, however she won't listen and you will have to fight her. She can turn invisible, however if you have Superior Moon Dust and throw one at her it will make the ability useless. After she is dead check the last victim's body, then go see Palmerin at the arena.
Note: When you reach the arena you may run into a Knight named Bors riding a horse who will converse with Percival if you hear what they are talking about it will start the There Can Be Only One quest.
Talk to Palmerin and after some small talk he will take Geralt to the stands. Guillaume will be fighting a handicapped Shaelmaar, however it will soon lose its handicap and Geralt will have to step in to help. Palmerin will help too, however he can get beat up by the Shaelmaar but he won't die so don't worry about him in the slightest. The Shaelmaar can be a tough opponent, however as Geralt will point out it's blind thus it uses sound to know where to attack. To make the fight easy use Aard while standing near a wall then dodge away, the Shaelmaar will crash into it and tip over making it vulnerable to attacks. After you defeat it Anna Henrietta will give you the option to finish it.
Important: If you spare the Shaelmaar it will count as "Proof of compassion" for There Can Be Only One.
Regardless Geralt will now be conversing with Anna Henrietta, she will take him to Damien de la Tour and tell him he is now the owner Corvo Bianco, which Geralt will point out is the morgue where he fought the Bruxa. Now it's time to ask Damien for details about the victims, after learning everything Geralt will deduce that the next victim will be Milton de Peyrac-Peyran. Anna Henrietta will reveal that all 4 were once a team and agree with Geralt, then decide to find him, problem is he is already at the celebration, now follow her on Roach to the party.
Finding the Bunny
Anna Henrietta will decide that breaking the rules of the game is necessary to save Milton. To find him, you will need the unicorn's horn, Golden fish, and the Phoenix egg. Anna Henrietta will go get the egg while Geralt will get the fish and the clue.
Apart from finding the key and making your way to the Milton's hiding spot, the rest of the objectives of this part of the quest are actually optional. While the intended way of progressing is retrieving the key and the clue from the horn of a unicorn and then meeting up with Anna Henrietta to solve a riddle, if the player already knows where Milton is hiding, they can go directly there after retrieving the key.
To find the fish, you need to dive into the water. There are multiple under the water, but only one of them – a golden one – holds the key while the rest contain sweets. If you find the right fish the first or the second time, you get the key instantly. If you pick the wrong fish twice in a row, someone else catches the fish from under Geralt's nose, leading to a cutscene of Geralt unceremoniously nabbing the fish from them and breaking it to get the key. If you wish to find the correct fish on your own then it's best not to use witcher senses to locate it, as the glowing outlines make it harder to differentiate the fish by color.
To get the horn you need to reach the "Unicorn". The animal, however, will run away when approached, and you need to either gain its trust with treats or use Axii to calm it. Using Axii will cause some other partygoers to accuse Geralt of cheating and try to fight him. You can use Axii here as well (does not require "Delusion"), or have a fistfight with the men.
Once you have both clues go back to Anna Henrietta who will just be taking the egg from a lady that has it. Now you have to solve the puzzle, the correct answer is "Greenhouse." If you guess wrong, Anna Henrietta will guess the correct answer instead. Regardless, the quest will end here and instantly continue to the next main quest, Blood Run.
Important: If you guess the correct answer it will count as "Proof of wisdom" for There Can Be Only One.
- No sooner had Geralt arrived in Toussaint than he got his first taste of the local color. As he was clip-clopping along the high road, chit-chatting with Milton and Palmerin, a most unusual sight unfolded before his eyes. Here was a knight, with all the expected accoutrements, charging headlong at a windmill! The situation became clear a moment later when a giant strode from behind the windmill and charged right back at the knight. Before anyone could say "Only in Toussaint," the witcher and all three knights were swinging away at the brute, amidst the freshly crumbled ruins of the mill and a herd of panic-stricken sheep.
- At long last the giant lay defeated, and the men who had vanquished it could make their introductions, then engage in the kind of conversation that oft happens over a fresh monster corpse. The young giant slayer gave the three arrivals fresh tidings – the Beast had struck again. The body of its most recent victim now lay on a riverbank nearby. Geralt decided he needed to see it and explore the crime scene, while Milton thought it both wise and courteous to accompany the witcher.
- Geralt failed to find the victim's body on the riverbank. It seemed the Ducal Guard had removed it to the cool cellars of the Corvo Bianco Estate. Ever the ferreter, however, Geralt did spot something the soldiers had overlooked. Based on the item, and with Milton's help, he established the identity of the Beast's most recent victim. Yet he failed to divine the species, genus, or family of the creature that had perpetrated the crime. Only an autopsy could help him do that. So Geralt set off for Corvo Bianco, alone this time as duties at court had called Milton to the Ducal Palace.
- Alas, something wicked had arrived at Corvo Bianco Vineyard. As the witcher drew near the estate, yet was still at some distance, battle sounds reached his ears. On arriving, he saw the bodies of guardsmen, murdered just moments before by a bruxa. The witcher promptly defeated the vampiress, who was not the Beast itself but was clearly in league with it. Yet Geralt could not guess at the link between them nor at the identity of the creature that had inspired the bruxa's rampage through the vineyard. The witcher needed information on the Beast's previous victims. He supposed the duchess might have this and thus set off to find her.
- Anna Henrietta's time was precious. To get an audience with her was never an easy feat. Even more so in those days, as the duchess was overseeing a chivalric tourney playing out on tourney grounds outside the walls of Toussaint's capital. Yet in the end Geralt faced the one who had summoned him. As they related what each had learned about the Beast, thus pooling their knowledge and hypotheses, they deduced the likely identity of its next victim, who could very well prove to be Milton de Peyrac-Peyran.
- Geralt and Anna Henrietta rushed like rabbits through the palace gardens. Ironically, at the time the gardens were the venue for a game of Hunt the Hare. Milton had been assigned the title role. The knight, having donned a bunny rabbit costume, sat hiding in the gardens, waiting to be found by the game's participants based on clues they could win by completing various challenges. Yet the duchess and the witcher could spare no time for such nonsense and set out to win the clues by breaking the rules.
- Having assembled the clues, Geralt and Anna Henrietta had concluded that Milton was hiding in a greenhouse. They had set off to find him post haste. Alas, they were too late. Amidst lush vegetation, they found Milton's rapidly cooling corpse. The murderer stood over it. As the witcher stepped towards him, the killer dashed off. Thus ended the first stage of Geralt's investigation. And thus began his mad pursuit of the murderer.
- Defeat the giant. (13 + 450)
- Follow Milton to the place where the body was found.
- Use your Witcher Senses to search the riverbank.
- Use your Witcher Senses to search the riverbank for signs of the guardsmen's activities.
- Defeat the necrophages. (50)
- Use your Witcher Senses to search the nets for clues the guardsmen might have overlooked.
- Talk to Milton about your findings.
- Follow Milton to the inn to ask if anyone saw where the body was taken.
- Go to Corvo Bianco and examine the body kept in its cellar.
- Use your Witcher Senses to determine what kind of monster killed the guards.
- Look for the body of the Beast's victim in Corvo Bianco's cellar.
- [Optional] Read the bruxa Bestiary entry to prepare for the fight. (150)
- [Optional] Use your Witcher Senses to investigate the site of the massacre.
- Find the Beast's victim's body in the cellar.
- Defeat the bruxa. (500)
- Examine the body of the Beast's victim. (150)
- Find Palmerin and ask him to take you to the duchess.
- Defeat the shaelmaar. (300 + 100)
- Follow the duchess to the palace gardens.
- Look for the "unicorn" in the clearing in the palace gardens.
- Retrieve the golden fish from the pond.
- Meet the duchess to assemble the clues and learn where Milton is hiding. (200)
- After the fight with the Shaelmaar, you can choose to kill or spare the monster. If you choose to spare it, it will count as proof of Compassion for the quest There Can Be Only One.
- On the small bridge over a small creek that later turns into a waterfall, you can find a crying woman and a man desperately trying to find her lost ring. The ring is located right below the waterfall, a short way following the creek. Then you can return the ring to the woman, and she will start dancing out of happiness.
- Take the ripe apple or basket of carrots to the "unicorn" to gain its trust (150). Alternatively, cast Axii on it to calm it immediately (150), but this will initiate an encounter with some courtiers that may lead to a fistfight if not calmed with more Axii (40).
- To find the correct golden fish in the pond with the key, it is the fish closest to the shore in the southwest without any candy or toffee. (150)
- The answer to the riddle is "Greenhouse". If Geralt answers it right, the player gets 200.
- If Geralt returns to the Greenhouse after facing the beast, he can find and loot a Hare Mask which Geralt can wear.
- Once you have the key you can go directly to the greenhouse, ending the quest without getting the clue from the unicorn nor doing the riddle.