This story is a sequel to Dr Whooves and the Classical Moon

When the Tardis lands unexpectedly in Canterlot the bumpy landing leaves the Doctors Companion Octavia in the lurch when it takes off again whisking the Doctor across time and space without her, leaving Octavia at the mercy of whomever finds her, meanwhile the Doctor gets a vision of the future while desperate to retrieve his companion lost in an unfamiliar time.