In *Kingdom Come: Deliverance 2*, Rosa's book side quest is easy to miss, and failing it means missing out on a chance to romance Rosa. To unlock this side quest, you must first complete the "Via Argentum" quest and start "Taking French Leave." After helping the Ruthard family with Vavak, speak with Rosa to learn about a secret passage into Maleshov that you can use to rescue Hans. Rosa will then request you to find her book while you're there. Ask her about the specific book and promise to retrieve it, officially starting the "Rosa's Book" quest.
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You can only complete this quest during the "Taking French Leave" mission. If you leave Maleshov with Hans without finding the book, the quest fails, and you'll miss the opportunity to deepen your relationship with Rosa. Fortunately, the book is located on your path to Hans' room.
Upon entering Maleshov, head towards the largest tower where Hans is located at the top. Use the stairs on the side of the building to enter the tower. Sneak inside and find another set of stairs near a small kitchen. Wait in the kitchen until the guards upstairs leave the tower.
Screenshot by The Escapist
Next, sneak up the stairs to find a room with Lady Ofka. She's facing the fireplace, allowing you to sneak up and knock her out. Take the keys from her body, the keys from the podium, and the sword from the chest in her room. In this room, you'll find Rosa's book to the right of the fireplace in a window alcove. Pick up the red book, and your objective updates to return it to Rosa.
Screenshot by The Escapist
While in the area, don't forget to grab another sword from the chest in the adjacent room. This will save you time later when you meet Hans, as you'll need two weapons for him and his unexpected guest. After securing the book and the swords, head to the top level and unlock the door on the left to trigger a cutscene.
Following the cutscene, continue with "Taking French Leave." Although Hans refuses to use the passageway, you can still work towards romancing him by choosing the dialogue option with a heart, provided you made the same choice in Trosky. Sneak to the stables on the north side of Maleshov, dealing with guards as needed. Clear a path, signal Hans, and ensure he reaches the stables safely.
Once you open the gate, another cutscene will conclude the quest. After it ends, return to Kuttenberg City and visit Ruthard Palace to deliver Rosa's book, completing the "Rosa's Book" side quest in *Kingdom Come: Deliverance 2*.
