In Tarclaver, Helen told Clara via email, there are libraries that are partly in buildings and partly underground. They stretch for miles and miles. There are Library guards who patrol what you can look at depending on who you are. But they don't bother with patrolling the ancient map room. "And there I found many maps of the area."

The maps that Clara had hacked from her father's system were not as detailed. Thus, it was Helen, who found the hill where they would meet. A hill top would allow them to definitively locate a meeting place in the wilderness. There, they would meet at noon on the 7th day after they started.