Case File #6 begins with the boys in New York City (once again), but this time they are there to visit “Uncle” Hugh Hunt, an old army buddy of their dad’s who is now an Insurance executive. While having lunch at a Russian restaurant, Hunt sees a message inscribed in the bottom of his teacup and his face goes pale. Two Russians calling themselves Feodor and Oleg then abduct him at gun point and spirit him away.
The boys are then apprehended by a government agent named Starkey. After a long exposition about how Fenton Hardy and Hugh Hunt actually worked for Army counterintelligence as spy catchers, after which Hunt founded his own Government Agency of Fiction, Starkey informs the boys that he suspects Hunt of selling secrets to the Soviets. He sends them to San Francisco to investigate and retrieve Hunt if possible.
After an initial encounter with Feodor, Oleg and Hunt, which ends with the boys having to jump off the Golden Gate Bridge into the Bay, the boys stumble upon a thief named Charity who wants to steal an Inca era crown from the Embracadero Museum. Feodor and Oleg also want Hunt to help them steal the exact same crown.
When Starkey tries to kill the boys with a thermite bomb, the boys tail him - and find him chatting away with Feodor! Who seems to have a perfect American accent. Seeing the crown as the center of this whole mess, the boys decide to steal it themselves. After a successful heist, Charity intercepts them and tries to snatch the crown away. To the boys’ utter shock, she flings the crown back, claiming that it is a fake!!
All the factions involved finally converge at a warehouse owned by the Embracadero where the truth beyond the whole issue is divulged and Hunt is saved.
Tropes found here are:
- All Chinese People Know Kung-Fu: Subverted with Kwan and Tony, the thugs from Chinatown Charity has hired to assist her. At first, Joe expects them to display martial arts techniques. Instead, they just engage in street fighting, which Joe is no stranger to. He takes them down easily.
- The Bad Guy Wins: Not Starkey, the main Big Bad, who is arrested and brought to justice at the end. However, when the Hardy Boys and Hunt go to retrieve the real crown from the safe at the end, they find that Charity has already stolen it and gotten away scot-free. This is also Downplayed, since Charity is more of a Wild Card and certainly A Lighter Shade of Black than Starkey.
- Batman Gambit: Starkey lies to Hunt about how long the latter has to live after taking poison—claiming it will kill him in three days—because he knows Hunt will try to steal the technology early and then spend the rest of the time trying to bring Starkey down. It actually only takes a bit more than two days, and by the time Starkey reveals this, Hunt only has about a half hour left.
- Caught on Tape: Joe reveals in the denouement that he was able to use Hunt's tape recorder to record their final confrontation with Starkey. Hunt states that this, along with Starkey's files, will be all they need to send him to prison.
- Classy Cat-Burglar: Charity just wants to steal a crown.
- Double Agent: Starkey, the Big Bad, turns out to be this. What's more, Hugh Hunt is revealed to be the person Espionage Resources sent to investigate him—much to Starkey's horror when he learns this, since he realizes that his attempted Frame-Up won't work and he'll be the immediate prime suspect in Hunt's death.
- Even Evil Has Standards: Charity's not actually evil, and is definitely A Lighter Shade of Black than the Big Bad, but she is still a thief who captures one or both of the boys multiple times. However, when she manages to get the antidote to Hunt's poison and is initially only willing to hand it over in exchange for the real crown, she finally gives it to Joe practically for free (just in exchange for a boat so she can make a getaway) once he makes it very clear that Hunt is going to die otherwise, because she doesn’t want to be involved in the dirtier dealings of the spy world.
- Fake Russian: In-universe. Feodor and Oleg are clearly American agents pretending to be Russians. Normally an experienced spymaster like Hunt should be able to spot this. But, as Frank states, “He has to play along because he’s been poisoned by them”. Apparently other intelligence agents fall for it, too, though.
- Girl of the Week: Charity is a variation. She acts flirtatious with Joe (who is a bit attracted to her) and invokes
Foe Yay with him, but is only on her own side, and primarily works against the Hardys for most of the book, though she does help them at the climax of the story. - The Good, the Bad, and the Evil: The Hardy Boys and their Uncle Hugh are, of course, the Good, seeking to bring all the bad guys to justice. Charity, a Classy Cat-Burglar who wants to steal a crown for profit and doesn't want to be involved in espionage or murder, is the Bad, and helps the Hardys at the end against the Evil: Starkey, an Espionage Resources Double Agent, and his underlings, who want to commit espionage by selling US secrets to foreign countries, poisons Uncle Hugh, and tries to kill everybody else multiple times during the story.
- Government Agency of Fiction: United States Espionage Resources, the agency that Hugh Hunt founded.
- Covert Group with Mundane Front: Espionage Resources operates under the guise of an insurance company, Transmutual Indemnity.
- The Heist: Frank and Joe have to steal a crown from the Embracadero museum in San Francisco to trade it for the antidote to Hunt's poison.
- Honorary Uncle: Hugh Hunt is an old friend of Fenton Hardy's, and the boys address and refer to him as "Uncle Hugh" throughout the story.
- Papa Wolf: "Uncle Hugh" is protective towards both of the Hardy Boys, his honorary nephews, at different times:
- Near the beginning, when Hugh is being abducted and Joe attempts to save him, the former tries to urge the latter to run away. When Joe is then cornered and almost executed at gunpoint by one of the fake Russian mooks, Hugh struggles, in a desperate attempt to stop the thug, hard enough to distract him so Joe can turn the tables.
- Later, the fake Russians catch Frank hiding in the apartment eavesdropping on them, and almost shoot him on the spot. Hugh objects, and while he claims that it's because he just doesn't want them to kill Frank right there (since he has to play along with Starkey and his men due to his poisoning), once they take Frank elsewhere to kill him by throwing him off a bridge, Hugh follows them in disguise, provides the means for Joe to rescue him, and reassures Frank later that he would have stepped in personally to save him if he'd had to.
- Poison and Cure Gambit: Starkey has Hunt's tea spiked with a slow-acting poison to force Hunt to steal a duplicate crown that contains fiber optic tech (which Starkey can then sell to foreign nations) in exchange for receiving the cure. What's more, he also pulls a Batman Gambit (see above) by lying about how long the poison will take to kill him.
- Stolen MacGuffin Reveal: Inverted. The boys and Charity assume they’ve stolen a golden crown, but Charity notices it is not cold to the touch. Turns out, the crown was duplicated so proprietary fiber optic technology can be smuggled out of the US.
- Tampering with Food and Drink: Hugh Hunt’s Russian tea is poisoned.
- Token Good Teammate: In hindsight, after Espionage Resources appears in three books, Hugh Hunt seems to be its only benevolent agent we meet; every other named character from the agency is an Obstructive Bureaucrat at best, and most of them are Double Agents or thugs working for said double agents.
- We Will Meet Again: The book ends with the boys having a feeling that they'll cross paths with Charity again someday. This does indeed happen in "Thick as Thieves" (Book #29).
- Wild Card: Charity. She's also after the crown, but unlike the Espionage Resources spies in the book, she wants the real one, since she's simply a Classy Cat-Burglar who only wants the money and doesn't want to get involved in killing or espionage. She kidnaps one or both boys on multiple occasions during the book, but is also working against both Starkey and Hunt, and in the end, is able to get her hands on Hunt's poison antidote and willingly hands it over to Joe without needing too much convincing. Summed up best by this line of dialogue:Charity: (to Joe) Aren't we both after the same thing?
Joe: Yes, I guess we are. Whose side are you on?
Charity: On my side, darling. Of course.
