Ghost in the Holly House Well. The Mystery Busters, #2

The Mystery Busters are soon drawn into another bewildering adventure when one afternoon, Becky hears a strange spectral voice coming from the old well at the bottom of her garden. A camp-over is organised with her friends Helayna, Tom and Alex, and an additional guest, Kurt Simmons, the slightly gothy kid from school that a lot of the girls like, Becky included. The investigation that ensues quickly leads to catastrophe when Becky, Tom and William end up slipping into the waters of the well and then into another world beneath, closely followed by their faithful friends.
Here they find themselves being called upon to solve a sinister crime that happened many years before. As they struggle with the dark forces ranged against them, the children experience the magnificence of time travel, the menacing behaviour of a powerful witch, and they meet again many of the dark beings from their previous adventure. They soon come to realise that the mystery they are dealing with is intricately entwined with the results of their first foray into this hidden otherworld.
Are they being hunted by the dark entities they previously defeated? And will they escape this time, or be forced to stay underground forever?This is the second book in Debbie Reiber's Mystery Busters trilogy, to be followed by Spellbound at the Smithy.