The Mystery Door and The Magic Lamp, Paperback

The four friends could not believe what Flo had just said. She wanted them to go to Morocco to collect something very precious for her.
But they were only twelve. How could they possibly go off to Morocco on their own?
Anyway how would they get there and back?
And what was so precious about what Flo wanted them to collect?
'I want you to pick up a magic lamp that was stolen from me a very long time ago, ' Flo had told them. 'It was given to me by my grandad and is now, probably the only one left in the world.'
What could they say? It sounded so exciting