Journey's Beginning

The Twelfth Doctor has his companion, Doctor Owen Harper, on the TARDIS when his Metacrisis self, now named John Smith, turns up, having broken through from the parallel Earth after the death of Rose Tyler. John is as dangerous as he was when he committed genocide of the Daleks, having snatched a regenerative cycle from a parallel Time Lady, killing her in the process. Soon, his daughter, Eve Jackie Smith, turns up too, at eight years old. The four try to cope with saving Earth from a new threat, at the same time as keeping John from endangering any lives he feels necessary.