In *Kingdom Come: Deliverance 2*, a crucial side quest, easily missed and impossible to replay, involves retrieving Rosa's book. This guide ensures you don't miss this opportunity.
Unlocking Rosa's Book Side Quest
Before Rosa requests your assistance, complete the "Via Argentum" quest and begin "Taking French Leave." After resolving the Vavak situation with the Ruthard family (through diplomacy or force), speak with Rosa. She'll reveal a secret passage to Maleshov, crucial for rescuing Hans, and then ask you to retrieve her book. Inquire about the book's specifics and promise to find it to initiate the "Rosa's Book" quest. This quest is only available during "Taking French Leave." Leaving Maleshov without the book results in quest failure and prevents a potential romance with Rosa.

Locating Rosa's Book in Maleshov
Upon entering Maleshov, Hans is located in the tallest tower. Use the external stairs to access the tower's interior. Inside, locate another stairwell and a small kitchen. Wait in the kitchen until the guards above leave the tower.

Stealthily ascend the stairs to a room occupied by Lady Ofka. Knock her out, and collect the keys from her person, the podium, and the sword from the chest. Rosa's book is located in a red volume within a window alcove to the right of the fireplace. Grab it, and your objective will update to returning the book to Rosa.

While in this area, acquire the sword from the adjacent room's chest. This will save time later, as you'll need two weapons for Hans and his unexpected guest. Proceed to the top floor and unlock the door on the left to trigger a cutscene.
Completing the Quest
Following the cutscene, continue "Taking French Leave." Guide Hans to the stables, neutralizing guards along the way. After the final cutscene, return to Kuttenberg City and deliver Rosa's book to her at Ruthard Palace, concluding the quest in Kingdom Come: Deliverance 2.