Lia & Kendra Pierro Walkthrough Part 10

Back at Lia's house have Rosa use the Key on the front door. As soon as Rosa is inside have her take the key that is hanging on the wall by the door. Then have her head through the door on the far right which leads to the basement. Once Rosa is there you can have her interact with the big shelf to have her try and move it.

This will trigger a conversation with Lia. To keep things short just tell her you are the bestower and push her for details on what is going on. When she says she won't say more until you have helped Kendra you can end the conversation.