Not that the kids know the situations are dangerous. That's one thing I liked about the characters. They are kids with short attention spans who forget about their quest because they are distracted by a carnival or want to lay out in the sun. Their imaginations interfere with their focus at times and it is endearing and also diffuses what might scare some. Others might find it annoying because it slows down the plot and as a reader you might be tearing your hair and shaking the book saying, "What are they thinking? They have to hurry or the bad guys will get there!"
I found myself more annoyed with the tension technique that comes from the kids or adults misleading the three kids on purpose or people miscommunicating with each other. This was used too many times and it is something I'm biased against. For instance, Jane should be telling Uncle Merry, Simon, and Barney about the vicar and his interest in the map but she doesn't because she doesn't think it is important. She's pretty bright through most of the story so I'm not buying that reasoning. Later, she makes the connection and it is pretty obvious the device was used to move the story forward. This happens again with other characters such as Barney and Mrs. Palk and I found it contrived and boring after awhile.
The setting has great descriptions and its easy to imagine this village on the harbor. The villains are one dimensional. They represent the Dark and sometimes appear nice and fun to the three kids. This is a good reminder that not everyone can be judged by outward appearances. The parents in the story are oblivious to what is happening with their kids and the quest. I wasn't quite sure why one villain had more power over the flunkies who served him. Perhaps the sequel will explain more of their relationships.
Jane is more stereotypical of a girl raised in the 1970's. She objects to her brother's dirty hands, wants to please those around her, it a bit of a sissy on the adventure having to be carried because she's so afraid, carries a spool of thread in her jacket, and who wants to tell parents about old manuscript. The mother is also presented as the stereotypical flakey artist. I did enjoy the voice of the characters with a Cornish accent, especially how they always said, "midear."
The plot was predictable and the clues weren't very interesting. The fantasy elements are all there in this book, it just didn't grab my interest. I'm going to read book 2 because it won a Newbery award. Cooper must have nailed it better than this one. I'm sure hoping so!