The 39 Clues Unstoppable,

Jeff Hirsch (book two of breakaway).

A group of kids are trying to find Atlantis and stop a man named pierce,

A group of kids are trying to find a underwater world called Atlantis and are trying to stop a man named pierce why'll trying to find Atlantis.

Chapter 16

One day in a hotel,

A man came to the room they were in and said there was a fire on the top of the hotel so they looked out the window and there was a lot of police and pierces men dressed as FBI so they jumped out the window and jumped across roofs of buildings till they got away from the police and pierces men.