Note: For those looking to get the Card Collector achievement, this quest must be completed.
You can pick up this quest a number of ways, though the easiest is during the main quest starting with Broken Flowers, where you meet Geralt's old friend, Zoltan. Once beaten he'll give 25 and the Eithné card. If he's the first one you met and beat out of the group, he'll direct you to play Vernon Roche, who's hiding out at Temerian Partisan Hideout.
If you haven't already met Roche, head out and after a small conversation with one of his men, Roche will appear and will be available to play. Once he's beaten he'll give 25 and the Saesenthessis card. If you haven't already played Lambert, he'll then direct you to play your fellow witcher, though depending on where you are in various quests, you'll have to wait a bit on this. He'll also hint at another player but won't drop his name if you're too early in the main quest line.
The quickest way outside the main storyline to play Lambert is by doing the secondary quest Following the Thread and continue the quest until you're given the objective to meet him at The Nowhere Inn. When you meet him there, when given the chance to say "let's go" or "I'll meet you there" pick the latter and Lambert will begin to walk away. Talk to him as quickly as possible (if he moves too far away from you he'll disappear to the next quest location) and challenge him to a game of gwent. If you already did his quest and didn't challenge him then, continue the main storyline as normal and you'll eventually be able to challenge him again at Kaer Morhen. Beating him at either location gives another 25 and the Triss Merigold card.
- Gwent is played for pleasure, a pleasure that is highest when playing in good company - and the best company of all is that of old and true friends. Geralt thus sought out some of his long-time companions for a hand or two of gwent - and the chance to win powerful cards from each of them.
- Geralt had a wonderful time slapping down cards with familiar faces and added several powerful new cards to his collection while he was at it.
- Win a unique card from Vernon Roche.
- Win a unique card from Thaler.
- When you get a chance, win a unique card from Lambert.
- Win a unique card from Zoltan.