In Vol. 4 of this manga, we get the first real case of the Detective Boys, when a case of switched bags drops a treasure map in the kids lap.
Conan, as a teen in the body of a grade schooler, is initially not impressed by their childish guesses at its meaning, but eventually becomes more and more drawn in as the puzzle proves formidable even for him. This is a dynamic we'll see repeated a few times throughout the series, though it's strongest here, as Conan's still relatively new to the whole "kid's body" thing.
I love the dynamic between him and the Detective Boys though - they force him to take a different view of the world around him that I think can help in his deductions.
This volume also had a somewhat meh episode regarding a murder in an art museum and a fun three-parter with a bomb on a train.
In Vol. 5, we get to spend some time with Rachel's best friend Serena, first when she invites Rachel along to a reunion of her older sister's film group then when she gets to spend time at karaoke with a famous band. And in grand mystery tradition, murders follow them.
The film group story was okay, but I never got terribly invested in it. The karaoke one however felt a little more emotional - even Conan is struck by the way things turned out - and as a result worked a whole lot better. (Not that I dislike the first, or indeed any of the cases so far)
But the highlight of the issue was, for me at least, the cliffhanger at the end of the book. Someone turns up claiming to be Conan's mother and takes him away (though it feels a little odd to me how easily she gets away with this at the Moores' place). Conan's been in some tight situations before, but this one is the first since... well, the first that's really focused on *him* as a target. And it's a pretty intense story for a kids detective manga so far. :)
Vol. 6 gives us the conclusion - surprising and fun but kind of WTF - to the Conan kidnapping case. I mean, seriously, what sort of horrible parents does he HAVE? This is followed up by a decent story about an antiques dealer who was killed by one of the people he had a meeting with that day and died in a room slashed up by a samurai sword. The highlight of this one though was, again, the Detective Boys. This time, they see a body in a man's house - but when the police get there, it's disappeared without trace. The kids are forced to retreat as the police accuse them of being liars, but you *know* Conan at least isn't going to leave it there. The best part though was that the rest of the Detective Boys totally have his back. they may not have the adult understanding he does, but they're enthusiastic and they bring a different energy to the issues they're in. <3
The volume ends with another cliffhanger, as Conan is convinced a man they met at the festival has committed murder, but the man's using the photos Rachel took at the festival to prove his innocence.
Man, things really ramp up in volume 7. After we wrap up the cliffhanger from Vol. 6, we get two really fantastic cases.
First, Richard Moore is called to a remote island (bringing Rachel and Conan because a potential murder is the place for kids. Well, I guess they've seen so many bodies by this point, what's one more?) by a mysterious note and a half-million-yen retainer. They think he's been called to solve an old murder, but several more bodies turn up in less time than it takes to play the Moonlight Sonata. The truth about who's behind the crimes, and the note, and the why of it all were really engaging.
That's followed up by this volume's cliffhanger, involving a professional soccer player and a young boy in mortal peril, as well as a web of lies as the victims try to get Jimmy to help them. I *really* liked this one, it seems really well paced and so far isn't making too many leaps of logic that don't work for me. Definitely looking forward to the conclusion in Vol. 8!