Stone Idols.

Here is The Stone Idol Hardy boys mystery, and the point where I think the whole series jumped the shark. Wiki says its brought about by the popularity of Indiana Jones, but it really doesn't fit in with that. No tomb raiding or mysterious artefact apart from the aforementioned stone idol. Just a wild goose chase and two different stories that don't really gel together. There are at this point no differences between the US and UK texts. All spellings and terms are the same. So it's a choice of if you want either Mystery number 63 or 65. The story starts off with a newspaper advert and a number for the boys to call. A Mr Kimberley of South American Antiques reports that a stone idol from Easter Idol has gone missing. The boys travel to Chile where South American Antiquities have their headquarters and with a cryptic clue find it hidden behind a painting in the head office. And there it all unravels as its stolen again and they chase it across the Andes, take a break to work on a case for their dad in the Antarctic before heading back to Easter Island where the Idol is recovered. I won't spoil the end but it's a nothing mystery and for me jumps the shark. It seems that whoever ghost wrote this read Thor Heyerdahl's Aku-aku. So you get some facts on Easter Island and a visit to see the famous Moai Heads. I know this would carry on for 120 or so books give or take. But in the UK where the series ended with the 87th, this is the equivalent of the last season of a popular show where they officially ran out of ideas. Anyway both can be found for reading here US and here UK.