Series numeration from www.goodreads.com.

Alex Cross' son, Ali, is eager to follow in his father's footsteps as a detective, but when his best friend goes missing, what price will he have to pay to solve the mystery?

Ali Cross is determined to follow in the footsteps of his father, former detective and FBI agent Alex Cross. When Ali's best friend Gabe goes missing, Ali knows that with every passing day, the less likely Gabe will be found. This is Ali's very first case. If he inherited any of his dad's detective skills, it's time for them to kick in! -- adapted from jacket