I remember that my friend (whose mother used to drive us home from school every day, and whose father was, like my father, one of the very few people that actually owned a home computer back in the days when these books were popular) owned this book and I owned Island of Secrets and thus, as it turned out, together we owned the set. I think that he owned some of the other Usborne computer books, and I know that I still have some of the books: three of them are here in Melbourne with me (while a forth one is back in Adelaide). The other interesting thing that I have discovered is that you can play this game online
here. Unfortunately I haven't found one for the other book, though you can still download it from one of the Commodore 64 sites that seem to be scattered across the internet (even now, twenty years after the computer, and the company that originally made it, have ceased to exist, that computer's legacy is still evident – hey, I still play games on the emulator that I have).
Anyway, this book (and the game that is attached to it) is much the same as 'Island of Secrets'. Not that the games are the same, no, they are both different. What I mean is that the books work on a similar format. In fact you cannot properly play the game without the book (and that is ignoring the fact that you need the book to type in the game, unless of course you knew somebody who had already done it and can get it from them, but you still need the book) because the book contains essential information required to complete the game.
Like the 'Island of Secrets', this book contains the background to the story, two pages outlining the people that you will encounter (or maybe not people, considering one of them is a ghost, and a ghost is technically, in the human being sense of the word people, not really a person, and even then if a ghost is considered a person, this ghost is not human because it is the ghost of a goblin, but then you know what I mean – I hope) and then a couple of pages that outline some of the important locations you will inevitably visit. After that there is the program which you have to manually type in (well, no you don't because this is 2014 and we have the internet, and this game is on a website that you can play it over the internet, but back when this book was originally released things were a lot different).
Oh, and I have just realised that I have spent all this time (relatively speaking) rambling on about the days of the Commodore 64 and I haven't actually said anything about this game. Well, it is an adventure game, and where Island of Secrets had a science-fiction setting, this one has a fantasy setting. Basically the land in which you live was one a peaceful land, but it was invaded by a horde that look suspiciously like Mongols, and pretty much all of the people were enslaved, that is after the important people were killed. However the child of the queen was secreted away, and when he grew up he went on a quest to free the land, only to be randomly killed by some bandits. This leaves it up to you, the anonymous, not so very Hollywood hero (because the hero died in a very unhollywood way) who will go off and attempt to save the land from the evil, look suspiciously like Mongol, horde.