Goodreads Singapore discussion

This is a long shot but I'm gonna try: to find a book of a title I can't remember. To READERS, many years ago, probably more than a decade ago, I read an adult thriller/mystery/fantasy fiction book about children who were being lured to another (promised to be) "magical", "happy" place which later in the end the children would have found themselves trapped in that place by evil. When the children managed to get back to their homes, I vaguely remember they found their parents many many years older than when they have last seen them though they themselves were probably still young (some time difference or time stood still for them when they were at the happy place). I thought it might have been a book by Dean Koontz but I've been searching for it for over a decade (haha yea >_<) and couldn't find any of his books like this so I thought I might have gotten the author wrong. Anyone has read a book like this or has any idea what is the title of this book?

have you tried Clive Barker's Thief of Time?

Robert Galbraith - Cormoran Strike's Series.
Currently, i am reading his 3rd installment titled Career of Evil. It's Thriller & mystery, definitely suited your taste!