The Ood also appear in the following episode, the two-part story "The End of Time". In this episode, the Doctor finally accepts Ood Sigma's message and returns to the Ood Sphere 100 years (in their time line) after having freed them in "Planet of the Ood". The Doctor discovers that the Ood's civilisation has advanced too rapidly, and that the Ood have developed the ability to see and project themselves through time itself. The Ood reveal that this is a consequence of time "bleeding", and the elders of the Ood show the Doctor the dreams and prophesies they have been seeing. At the end of part two, Ood Sigma appears again to the Doctor and gives him the encouragement to return to his TARDIS to complete his regeneration into the Eleventh Doctor.