You can start the quest by either talking to Jacquette who you can find near the Nilfgaardian Embassy, in which case she will be calling out to Geralt and you can haggle the price with her, by finding François le Goff near the cave located Northwest from the Beauclair Palace or lastly by strolling into the cave itself. If you find François at his camp he'll be asleep and snoring no matter what time it is, so wake him up.
Note: If you completed The Warble of a Smitten Knight Geralt can introduce himself with either of his Knight titles
After a short conversation François will agree it's time to fight the Grottore and you can offer to help him or tell him to get going. If you tell him to go alone you can still follow him or leave the area in which case he will die and the quest will update telling you to check on the knight, after you enter the cave you will find what's left of him and you will have the option to investigate and kill the monster by yourself. If you offer to help he will join your party and his health bar will be visible, however if you walk too far away he will die as well, so if you want him to live follow him into the cave.
Regardless after you investigate the main chamber thoroughly Geralt will deduce that the Grottore is a Spriggan, after which you will have to check your journal on how to deal with the beast. After you prepare yourself you have to burn the flowers using Igni to lure it out. The Grottore will summon Archespores during the fight, however you can actually use that to your advantage by using a Superior Golden Oriole, also if you are wearing Grandmaster Wolven armor, you can use it's ability to apply both Cursed oil and Relict oil simultaneously. After it's dead and François is still alive Geralt will converse with him and have 2 options, either convince him to return to Jacquette or tell him to do as he wishes in which case you get to keep the Grottore trophy, regardless it's time to return to Jacquette.
If François died she will be devastated and you get no reward, regardless whether you avenged him or not, in fact asking for a reward will anger her.
If François is alive and Geralt convinced him to return to her she will be very happy and tell him that they are getting married in a week and she will pay you your promised reward.
If François is alive and Geralt told him to do what he wants she will realise his true motives and break off their engagement but she will pay Geralt his reward nevertheless.
Important: Saving François will count as "Proof of Valor" for There Can Be Only One
Regardless on how the situation played out the quest ends there.
If Geralt starts the quest by first finding François or the cave:
- Few know just how nosy Geralt actually is. He rarely takes the path more frequently traveled, choosing instead to scale mountains, forge through dense brush and traverse many a wilderness. During one such foray through the largely unknown, he happened on a cave at the entrance of which lay numerous corpses. Before the witcher could begin to penetrate it, however, he was stopped by a young knight named François, who had vowed before his betrothed that he would kill the monster that dwelled within the cave.
If Geralt starts the quest by talking to Jacquette:
- Any semblance of false modesty aside, I can comfortably contend that my songs of Geralt's deeds are known the world over. The Duchy of Toussaint is no exception. There, my ballads praising our witcher's so oft demonstrated valor and honor remain popular to the extreme. So much so, that on one occasion it was chiefly thanks to my works that Geralt was offered a contract. A young noble lady, who had learned of the witcher solely from my thoroughly accurate descriptions, picked him out of a crowd and promptly begged him for aid. She was concerned for her fiancé, François, who had set out not long past to slay a monster in honor of his betrothed. The monster was known as Grottore, and the lady's beloved had not yet returned. The lady tasked the witcher with learning what had become of the young knight...
- If Geralt lets François run ahead and die:
- Alas, young François stood no chance against Grottore. He perished, pounded to a pulp by the terrible beast. Geralt could do nothing to bring François back from the dead, but he could avenge the young knight and at once rid the land of a dangerous beast. Thus he drew his silver sword, sent it into a whirl, and soon after Grottore's ample dome dangled from the trophy hook affixed to the witcher's saddle.
- If Geralt protects François:
- With Geralt's aid, the young François managed to defeat the fierce Grottore and thus fulfill the vow he had made.
- Geralt gives the trophy to François:
- Yet he showed an immense desire to postpone another vow – that customarily made in a chapel with one's previously betrothed at one's side. But the witcher reasoned with the knight, and François returned to his heart's captor to begin preparing for the day they would wed.
- Geralt keeps the trophy:
- Yet he proved unwilling to make another vow, the kind one customarily makes in a chapel with one's beloved at one's side. Instead of returning to his heart's captor he decided instead to set out in search of another monster he could face and conquer...
- Find François.
- See what happened to François. (if Geralt waits too long)
- Help François defeat Grottore.
- Find Grottore using your Witcher Senses.
- Read the Bestiary entry about Grottore.
- Return to François' beloved.
- In the Polish (Original) version the quest is called "Jeśli nie chcesz mojej zguby..." which means "If you do not wish my downfall". Which is a verse from the play wikipedia: Zemsta.