it is not that difficult if you really understand the instructions. these only becomes difficult if you don't know how to follow them especially if the instructions will just go into your ear and go out to the other.
the end of number the stars lines right up with the end of world war ii. this seems like a natural stopping point, because at the end of the war, the different threads of the story can all be woven together. sure, we already know that the rosens made it off to sweden safely, but fast forwarding to the end of the war assures us that all of our characters are safe and sound.
but wait a second. even with this tidy ending, we don't get closure on everything. we know what has happened to the johansens and to peter (r.i. but where are the rosens? where's ellen? what will her homecoming be like? will annemarie and ellen still be the friends that they used to be? or will their experiences in "different worlds" (10.4) have pushed them too far apart? what other questions would you like to hear answered?
and don't forget: at the end of number the stars, the nazis' reign has ended. but the healing—of copenhagen, of the jews—has barely begun.