This is the first book of the Case Files series, which was intended for a slightly older audience, as it contained more mature themes involving deaths, murders, relationship troubles, jealousy, dysfunctional families and so on. And the very first book pulls no punches - by killing off supporting character Iola Morton.
Tropes found here are
- Anyone Can Die: This book starts this trend off for the Hardy Boys by killing Iola.
- Bitter Almonds: This exact phrase is used to describe the smell of cyanide when one of the terrorist hijackers bites into her suicide pill.
- Cerebus Syndrome: Beginning with Iola’s death, this book wastes no time setting a darker tone.
- Deus Exit Machina: After keeping the Hardy Boys safe from the Assassins for the first half of the book, the Gray Man gets badly injured by a bomb explosion and ends up in the hospital for the rest of the story, leaving the boys and friends to take on Al Rousasa and stop his plans by themselves.
- Dirty Cop: Detective Sam Butler. That said, he wasn’t really dirty since he was Dead All Along.
- Disney Villain Death: Al Rousasa plunges to his death off a mall mezzanine when he falls over a railing, then loses his grip on Joe's hand when the latter tries to save him because it's covered with blood thanks to Al Rousasa cutting him with a knife.
- Get a Hold of Yourself, Man!: Frank has to knock Joe out to prevent him from running into a flaming car to try to save Iola.
- Government Agency of Fiction: The “Network”, which is supposedly more secretive than the CIA.
- If You Kill Him, You Will Be Just Like Him!: Joe initially wants to kick Al Rousasa off a mezzanine to his death. But then he decides he’d be no better than the assassin if he does so, and instead tries to pull him back up.
- Kill and Replace: Al Rousasa killed the original Detective Sam Butler before the events of the story and took his place to get at all his targets in Bayport.
- Ridiculously Average Guy: The Gray Man is so nondescript and average looking, he can very easily blend into a crowd.
- Save the Villain: Joe tries to do this for Al Rousasa, who killed his girlfriend, by pulling him back up when he falls off the mezzanine. Thanks to Joe's hand still being slick with blood from the terrorist cutting his hand with a knife, it doesn't work, and Al Rousasa falls to his death anyway.
- Sudden Sequel Death Syndrome: Iola Morton is killed by a bomb explosion right before the opening of this book.
