.. Getting Zoe's poster

I bet you can grab the poster if you get Zoe out of her room.

Maybe if there was something that interests her in one of the other rooms.

Talk to her and ask about the posters.

Yup. Maybe go check other rooms now. ( Go to the living room. )

Turn on the television in the living room.

Go tell Zoe about their concert. She will leave the room.

You can now grab the poster.

It has one of the symbols needed to open the cryptex ( Open the wooden box in your inventory to find the cryptex. ) . You need to exmine the poster in your inventory.