Oh, this is so wonderful. Ian and Barbara! Also Evelyn and Romana! *glee* I loved them all, from quiet to happy to bittersweet (that ending with Nine *wibble*) but possibly my favourite was part four, because not only does it have Four and Romana being seventy-six shades of awesome (ie. your characterisation is great), it has Ian and Barbara looking up at the sky and wondering whether aliens work by the saying 'if humans don't go to us, we go to humans'. Well, in my head it does.