In the Mirror Universe the tyrannical Emperor Tiberius, once captain of the ISS Enterprise, had great success turning captured alien weaponry to his advantage. Until, that is, his failure to seize the tantalising advances of the ancient First Federation. Now, in the more peaceful universe of the United Federation of Planets, Tiberius sees his second chance. And a new ally will help him take it - his alter ego for whom he has nothing but contempt -...