I thought I was going to enjoy this book more with the two girls and two boys and female narrator format. It was mainly over-the-top eighties style excess and the males do nearly all the thinking anf talking and the females follow (one female is absent) so that very quickly reading the book just became a tedious game of "Can you stay wide enough awake to notice let alone solve the trivial mystery).
Nevertheless this sort of series was in many ways better than some of the mass-produced (and overly gendered) stuff available for children currently (2015) with outright consumerist values and the heterosexual matrix forced on younger and younger readers. So eighties shallowness was still in some ways naive and charming compared to the shallow, cynical marketisation of absolutly everything to children and their families now.
I mean you at least have to read a little bit critically to try to solve the mystery right? Maybe that is why this (still popular with children) genre is no longer so readily available!