The Impossible Clue
Dr. Learner had been working on a top-secret invisibility suit that everyone wants. Rumor has it he's disappeared under suspicious circumstances . . . literally. But is wacky science really behind his vanishing? Or is it something more sinister? Alice won't stop until she knows the truth . . .
The story has a good amount of adventure and some pulse pounding moments, but stops short of being gory or gruesome. Many of my students want blood and murder, but it's not necessarily the best thing for them! This is a nice compromise between the mysteries about neighborhood dogs being kidnapped, and the more young adult mysteries where people are murdered.
This has been reworked slightly and reset in the United States, somewhere near New York City. I'd be curious to see the original UK edition.