Into the Void

"Into the Void" is the eleventh episode in the eighth season of Doctor Who, which sees the return of Omega. It is the first part of two episodes, with the story concluded in The Infinite Realm.

Synopsis
"I don't care if some ancient presence is lurking beneath this planet, we have money to make!" - U.M.O representative

The White Guardian recalls the Doctor and his companions back to Earth, where he warns the Doctor that a great enemy is returning. As the TARDIS approaches Earth it suddenly crashes on a far distant planet, where the Doctor discovers a blackhole to an anti-matter universe. As the Doctor struggles to keep other humans on the planet from mining the planet, he discovers a far worse problem is steadily approaching.

Professor Yaphen and the U.M.O
When the Doctor and his companions arrive on the mysterious planet, they encounter Professor Yaphen and his team, along with representatives from the United Mining Organisation. Much to the Doctor’s advisement against it, the U.M.O begin to drill into the mysterious planet’s surface, uncovering an artefact the Doctor thought long since destroyed. As Professor Yaphen and his team uncover an ancient casket, they unwittingly cause the regeneration of Omega, who went into deep sleep after being banished by the Doctor in Arc of Infinity. Omega asserts control over the team and the U.M.O representatives, programming the planet into a giant vessel and transporting Omega back to his own realm. The Doctor only realises what is happening before it is too late.