Tintinrulz:
Anthony Horowitz, the scriptwriter, indicate that the second movie is unlikely to be The Seven Crystal Balls/Prisoners of the Sun
I think he’s only said that
Prisoners wouldn’t be the basis of the next one - I don’t know if that applies to
Crystal Balls as well.
My gut feeling is that they have been surprised by the success of the first film, and are now deciding to back peddle a bit on how fast they use up original books – if they plan to do further sequels after the third film, they don’t want to use up too many.
I could see them spinning things out a bit, and having the next one
Red Rackham, with a bit of
Crystal Balls, then the third the rest of
Crystal Balls and
Prisoners, then something like the
Moon books for a fourth?