I have recently watched the classic Doctor Who episode The Three Doctors again. starring William Hartnell, Patrick Troughton and Jon Pertwee it begins after A powerful superluminal signal is beamed to Earth, carrying with it an unusual energy creature that seems intent on capturing the Doctor. In the meantime, Gallifrey the homeworld of the Time Lords is also under siege, with all power being drained through a black hole. Trapped and desperate, the Time Lords break the First Law of Time, allowing the Doctor to aid himself by summoning his two previous incarnations from the past. Unfortunately, the First Doctor gets trapped in a time eddy. However the Second And Third Doctor are able investigate the origins of the creature and the black hole, while UNIT headquarters faces an attack by gel-like alien creatures. The First Doctor surmises that the black hole is a bridge between universes, so the other two Doctors allow the TARDIS to be swallowed up by the energy creature, which transports them, Dr Tyler, Jo Grant, Sergeant Benton and Brigadier Lethbridge-Stewart (Nicholas Courtney) into an antimatter universe.
Once in the Anti-Matter universe They are then captured by more gel-like alien creatures and are taken to meet a legendary Time Lord named Omega, who has managed to survive in the world of Anti Matter by using his scientific knowledge to create a domain for himself. Omega is venerated by the Time-Lords as he was the Solar Engineer who created the Supernova which powers Time-Lord Civilisation. However he was thought by the Time-lords to have been killed by the Supernova.
However Omega is not dead he is trapped in the world of Anti-Matter and is most aggrieved that the Time Lords abandoned him to his fate and wants to escape the Anti-Matter universe and wreak revenge on the Time-Lords. So he has summoned the Doctors here to take over the mental maintenance of the antimatter universe so he can escape. So the Doctors give Omega a proposition They will give him his freedom if he sends the others back to the positive matter universe. Omega agrees, however the time he has spent in the Anti Matter universe has had a bizarre effect on him and all does not go quite to plan….