Secrets. Lies. Promises. Sometimes keeping things inside is dangerous. Callie, Ted, Zara, and Nico are best friends. More than friends - they're like family to each other.

But since being embarrassed at school in a practical joke gone wrong, Ted has stopped talking to the rest of the gang. And when Callie, Zara and Nico discover that someone has been living in their school, and sleeping in the building at night, they decide to investigate - without Ted.