Nico nods I will give you the tour he takes her on the tour he gave everyone else(if you want to see what the tour is to go page two in pretty sure it's in the beginning ones) he gets Dylan's iris message and shadow travels to get him then comes back

Dylan had sent a iris message asking if nico could come get him as he did not want to go on the quest and possibly die he left a note before he left explaining why he left