This 'game' is mentioned on the box of UK Pico systems, and it's also in a list of games on the inside cover of other Storybooks, but doesn't appear in the online listings.
The only result Google returns is this page: http://www.humansoft.com/pico.html , which isn't a great deal of help, but thanks to the magic of the Wayback Machine can be re-constructed to this: http://web.archive.org/web/200311031....com/pico.html
Anyone know anything about it? Possibly a US game that was retitled for the UK?
I don't know if it was actually released or not since I've not seen one, but it probably deserves a Rumor Mill entry at least.
(man, I really think I should have better things to do with my time than trawl the internet for information on unreleased Pico games )