Chapter one of Apon Descending begins with the murder of Gordy Moot. Detective Simon Ash, along with another Detective, Morgan Ferris, who’s trying to horn in, begin their investigation. A mysterious series of arsons and murders follows, including the murder of Ash, when a bomb planted in his car explodes. Just moments before his murder, we had learned that Ferris and Ash are married. Meanwhile, a stranger surrounded in mystery wanders into the town of Apon named Jackson Moot, the nephew of Gordy, the first victim. Moot and Ferris begin investigating the series of crimes together and, along with Faye Valentine, who was working undercover in Apon as a forensics investigator, uncover the cause for all the mayhem buried deep below the town. Mystery solved, Ferris decides to join MASK and heads for Mexico.

In chapter two, MASK operatives Jackson Moot, Faye Valentine, Rook, and newly minted member Morgan Ferris are hired to cross the border to fight the Mexican drug cartels. Ferris quickly identifies a potential switch agent - 14 year old orphan and la Familia lieutenant Tayanna. Always accompanied by her two Xolo hounds Fiel and el Sombre, with whom she has an uncanny ability to communicate telepathically, it remains unclear until the end of the mission exactly whose side she’s on. After an early bloodbath, Moot is pulled from the mission leaving the mysterious Knight, along with veteran operators Valentine, Rook, Ferris, and Tayanna to finish the job.