The Nightmare Fields (Rebirth Story)

The Nightmare Fields was the third episode of the first series of Doctor Who Rebirth and the first full episode with Ood Theta as a companion for the Tenth Doctor.

The Nightmare Fields is one of the only episodes where the events of the episode had never actually happened and were all part of an induced dream state due to a Bodach having somehow gotten onto the TARDIS. This episode also features a cameo from Matt Smith's Eleventh Doctor which helps sell that the Rebirth Universe is an alternate universe.

Continuity

 * The enemy of the episode turns out to be a Bodach which puts The Doctor, and Theta into a dream-state. The Bodach's first originated in the ninth episode of K9 titled "Dream-Eaters". Bodach were creatures that would feed on dreams.
 * We see the alternate universe/main universe Eleventh Doctor (Matt Smith) who shows up due to various universes melding together. He mentions the Time Well, and how it's causing the breakdown in reality. This sets up the arc for Series 1.
 * In the Tenth Doctor's dream-state he must deal with hallucinations of some his past incarnations, and past companions.
 * The Tenth Doctor mentions he's been around for about 900 years.
 * The Doctor finds a bag of jelly babies in his pocket when the Fourth Doctor hallucination appears. His Sonic would also turn into a stick of celery with the arrival of the Fifth Doctor.
 * We see flashbacks to what cause The Eighth Doctor to become exiled from Gallifrey, which also could be said that the episode is a regeneration story showing the Eighth Doctor's regeneration into the Shalka Doctor.