All In by Jennifer Lynn Barnes

Cassie Hobbes and the FBI's team of gifted teenagers, the Naturals, are called to Las Vegas to investigate a string of brutal murders. The case is baffling: three victims in three days at three different casinos, each killed by a different method, and all without a single trace of the killer on any security feed. The only clue is a string of numbers tattooed on each victim's wrist.

As the team delves into the investigation, they discover the numbers are part of a complex mathematical pattern based on the Fibonacci sequence, suggesting a killer who is meticulously planning every move. The case becomes a high-stakes puzzle for Sloane, the group's statistical genius, as they race to predict where the killer will strike next.

Amidst the pressure of the investigation, Cassie is confronted with a devastating personal development: after five years, there has been a major breakthrough in the cold case of her mother's disappearance. Forced to confront new evidence, Cassie uncovers a shocking truth that links her mother's fate to the very killer they are hunting in Vegas. The discovery reveals a connection to a multi-generational secret society known as the Masters, setting the stage for a conspiracy far larger than anyone imagined and leading to a jaw-dropping cliffhanger that changes everything.