"Having saved the universe and restored peace at home, the Doctor and Liv go in search of their friend, Helen. Following a trail of breadcrumbs through space and time they discover an unsavoury conspiracy, and an old enemy lurking in the shadows, waiting. 1.1 Their Finest Hour by John Dorney. In the early days of the Second World War a strange and elusive craft attacks British targets. Could it be a German superweapon? Churchill calls fo ..."