Crooked Future was the sixth episode (not counting the Christmas Special) of the second series of Doctor Who Rebirth, and is the first guest-episode written by Brogan Young. It takes place on the research vessle, 'Nain Rouge' where a creature known as The Sorrow causes people to hallucinate, and commit suicide.

This episode features an unknown incarnation of The Doctor which turns out to be just a by-product of the Tenth Doctor's hallucinations due to the Sorrow.