Lillys ghosts pg. 85 fiction author Laura Ruby

What happens next in this book is that when Cassandra and Lilly get to her house to start working on the assignment, they start arguing about what should go where on the poster and how words are spelt. When they finally come to an agreement they hear something up stairs banging. Lilly was confused and thought her mother was shopping and her uncle was at work. They both looked at eachother curiously, then thought it might have just been the wind that made the house creek.  A little bit later they heard it again. 

What i think is going to be happening up stairs is that someone broke into their house and was trying to steel stuff from them because they had alot of money. 

A word that i didnt know was perpendicular.