I read a few more chapters of Nancy Drew and the Hardy Boys Super Mystery: Operation Titanic. Wow, that book has a long title.
Nancy and the FBI guys continue their investigation, although now it's more of a crime scene investigation than a stakeout. Thanks mostly to Nancy's bright ideas, they determine the killer is Amos Jericho, an ex-CIA agent who went rogue after the Cold War. Jericho's appearance is a shock to the FBI guys, who thought he died in a fire three years ago.
Clearly, Jericho is interested in the Titanic cruise. This is an upcoming cruise, run by billionaire Walter Welsch, in which they are going to raise the famous ship Titanic (or part of it, at least). Welsch himself shows up, and he offers Nancy free tickets. Free cruise tickets? A chance to see the Titanic get raised? A murderous CIA agent on the loose? How could Nancy not agree to go?
Meanwhile, the Hardy Boys are driving to some ocean research institute in Conneticut for their vacation. They get attacked by an incredibly determined team of assassins. The assassins wreck the Hardy Car, then force it off a cliff. The Hardys survive, of course, and they decide to split up for a dramatic chase scene. Frank goes into the swamp, where he gets attacked by a snake, while Joe tries to dodge guys on motorcycles, so he can call for help.
At no time do our heroes ever figure out who the gunmen are, or why the gunmen want them dead. Eventually, the Hardy Boys are captured alive. Things are tense as the gunmen try to pump them for information, but they end up being rescued by a helicopter. Looks like Joe's phone call for help worked!
That's the first third of the book. It's basically an extended chase sequence for the Hardy Boys, and an extended investigation for Nancy. I think Nancy's going to take her two best friends with her on the Titanic cruise; I'll have to keep reading and find out.