Doctor Who has just given viewers a fresh look at the Timeless Child - and dropped some major new clues as to her identity. The Timeless Child is the central mystery of Doctor Who season 12, a secret that led the Master to destroy his homeworld of Gallifrey. He set the Doctor on a path to discovering the truth behind an ancient falsehood, one that he believed redefined what it meant to be a Time Lord.

“They lied to us,” the Master told the Doctor, sounding mournful and shaken at whatever he had discovered. “Everything we were told was a lie. We are not who we think. You or I. The whole existence of our species - built on the lie of the Timeless Child.” The Time Lords have always been a secretive species, and this is hardly the first time they’ve been found guilty of deceit; but this sounds to be on a far different scale to ever before. So far, the Doctor has only caught glimpses of the Timeless Child, through what appears to be some kind of race memory.

The latest episode of Doctor Who, “Can You Hear Me?” saw the Doctor trapped in another vision of the Timeless Child. She was subjected to the “technology” of two Eternals, Zellin and Rakaya, which forced her to confront her deepest fear. This manifested in an extended form of the same vision, with the Master’s words echoing in the Doctor’s mind. It lasted a little longer this time, revealing that the Timeless Child was indeed stood at the foot of an ancient Gallifreyan citadel. What’s more, the camera lingered upon the skyline, revealing the Timeless Child contemplating what seems to be a portal or restrained energy sphere.

At first glance, this scene doesn’t reveal much. After all, the Timeless Child was first mentioned in Doctor Who season 11, episode 2 which provided much of the known information. In that episode, the Doctor found herself thrall to alien beings known as the Remnants, dangerous ribbon-creatures, who dug deep into her memories in order to find her worst fear. “We see… further back,” the Remnants whispered. “The Timeless Child… we see what’s hidden, even from yourself. The outcast, abandoned and unknown…” This fresh vision confirms the Timeless Child is the Doctor’s greatest fear, and possibly - given this appears to be a species memory - that of the entire Time Lord race.

But it’s the “portal” hanging over a Gallifreyan citadel is important. If the Timeless Child really is the dark secret at the heart of Time Lord history, then this is presumably a key event that has been rewritten by historians; perhaps it is even the moment when the Eye of Harmony, which powers all TARDISes, was created. Notice the citadel is absolutely deserted apart from the Timeless Child. This fits with the Remnants’ description of her as an outcast who is “abandoned and unknown” - and facing cosmic energies.

Hopefully it won’t be long before Doctor Who reveals just what those are.

More: Doctor Who: Ruth Origin, Timeline & Future Explained

Doctor Who continues on BBC America, Sundays at 8pm EST.