It's the journey to the center of the Dalek!
On Doctor Who Season 8 Episode 2 The Doctor is still questioning who he is. He doesn't question who the Daleks are, however, and when a good one is presented to him, he doesn't waste any time trying to "cure" it by going all "Innerspace" at the invitation of the Dalek himself!
But is the Dalek really sick, or is it just changing? The Doctor and Clara have differing opinions on that, and given The Doctor's current state of confusion about himself, he might not be the right person for the task.
Find out how it all goes down when you watch Doctor Who online!