Since Hacker has a secret device that can listen in on their conversations, Matt, Inez, Jackie, and Digit need to create a way to communicate with each other without Hacker knowing what they are saying. They decide to create a code and an accompanying ruleset so that both the sender and receiver can understand the message. Inez suggests using the page number, line number, and word number within the line of Digit's book, The Cyberchef, to communicate.
While investigating a major meth laboratory, Charlie and Megan recover a hard drive belonging to the primary meth distributor. Unfortunately, the disk had been badly damaged by the explosion of the meth lab. In spite of that - and luckily for the investigators - in many cases it is still possible to recover data on a badly damaged drive by making use of a computer's built-in redundancy in data. Essentially, even large portions of the files on a drive are lost or erased, because of symmetry and redundancy in most modern data storage, Charlie had a chance!