The Three Doctors (Doctor Who) the Third Doctor (Jon Pertwee) for help when Omega drains their civilisation's power. The serial opened the tenth anniversary year of the series, and features the first three Doctors all appearing in the same serial. This makes it the first "Doctor Who" story in which an earlier incarnation of the Doctor returns to the show. A superluminal signal is sent to Earth, carrying with it an energy blob that seems intent on capturing the Doctor. The homeworld of the Time Lords is also under siege, their power being drained through a black hole. Trapped themselves, and desperate to send help,
The Doctor (Doctor Who) the current Doctor having left his shields down when rebuilding the TARDIS following "Last of the Time Lords" and then accidentally crossing the Fifth Doctor's timeline, allowing the two TARDISes to merge. When the Tenth Doctor effortlessly averts the impending Belgium-sized hole in the Universe caused by this temporal anomaly, he reveals having known what to do because he saw himself do it as the Fifth Doctor and remembered. He goes on to tell the Fifth Doctor how fond he was of his incarnation and how he influences the current Doctor's personality. However, in their two meetings, the Second Doctor