In *Kingdom Come: Deliverance 2*, some side quests are easy to miss, and failing them can mean missing out on unique rewards or story elements. One such quest is "Rosa's Book," which requires careful timing and attention to detail to complete successfully.
To start the "Rosa's Book" quest, you must first complete the "Via Argentum" quest and initiate "Taking French Leave." During "Taking French Leave," you'll help the Ruthard family deal with Vavak, either through force or persuasion. After resolving this, you'll be directed to speak with Rosa. She'll inform you about a secret passage into Maleshov, which is crucial for rescuing Hans. While discussing the passage, Rosa will ask you to retrieve a book for her. Make sure to ask her which book it is and promise to bring it back to her, officially starting the "Rosa's Book" quest.
Upon entering Maleshov, head to the largest tower where Hans is located at the top. Use the stairs on the side of the building to reach the entrance. Sneak inside and find another set of stairs near a small kitchen. Hide in the kitchen until the guards upstairs leave the tower.
After the cutscene, continue with "Taking French Leave." Although Hans may not want to use the passageway, you can progress towards romancing him by choosing the heart dialogue option, provided you did the same in Trosky. Sneak to the stables on the north side of Maleshov, knocking out and hiding guards as necessary. Clear a path, signal Hans, and ensure he reaches the stables safely.
Open the gate to initiate another cutscene, concluding the quest. Once it ends, return to Kuttenberg City and stop by Ruthard Palace to deliver Rosa's book, completing the "Rosa's Book" quest in *Kingdom Come: Deliverance 2*.