Mummys case

 Getting down to the last 3 book released in the UK, here. FYI only Track of the Zombie and The Blackwing Puzzle to go. 

The boys are tasked with escorting a mummy back, via ship to Cairo, where it'll be unwrapped for the museum* but of course attract trouble along the way. One of those being, putting down a coup in the made up Mediterranean island of Rubassa, as part of a case their dad is investigating.

They also take in the sights of Egypt, getting a glimpse of the boy king, Tutankhamun's mask. Karnak and Luxor and later fly over Amarna, the heretic kingdom of the pharaoh Akhenaton or rather Ikhnaton as the book has him.   

Rubassa is an odd case that along with it's sister island Milbin, the book bills it as an ex British commonwealth possession in the Med. It seems to be a stand in for Malta and by dint Gozo, which are British territories in the Med. It's capital city is Loma and is on the cusp of a revolution. Probably when this  book was written it was referencing Cyprus, which the boys also visit as part of their guard duty. 

Sadly for them, Nicosia remains resolutely landlocked, which means their sailing up to dock is rather moot at this point.

There is only one change between UK and US editions, a line that says save your breath is now, don't hold your breath. You can read them here and here.