The Doctor stepped out of a room in the TARDIS with an odd looking pair of goggles.
"Astral goggles!"
"They will enable us to see those invisible beings?"
"Yes. Only had the properties to make one though" said the Doctor. "We're just next to where the Eye is and scans show none of its accomplices. So out we go!"
They had landed among the tombs, about 50 meters from where the ceremony had happened. The Doctor took the goggles off.
"The Assassins could be here!"
"Well you know the goggles make it surprisingly hard to see normally. Let's get this over with. I just need to finish gathering data on the Eye."
As they walked through the tombs the Eye opened again, glaring at them.
"Hello Eye" said the Doctor.
"Doctor... I have heard of you, Time Lord."
"You know, that's not so intimidating considering how many places I've been to" replied the Doctor. "And I wish that powerful, ancient rulers could be a bit less formal."
"You babble like a fool" said the Eye.
"And I've often been called a fool" said the Doctor. "But what do you want?"
"I want to spread out" said the Eye. "I want more to join me. I want my gaze to fall across the universe, through time and space. I saw many things... I see the moment of your birth and your future... but that is uncertain for one such as you, Doctor. I see the many times we meet."
"You really do go on" said the Doctor. "Can you see what I will do next?"
"There are many poss..."
The Doctor pulled a long, advanced-looking rod out of his pocket, which Kusla noticed should not have been able to contain it, and poked at the eye.
Its glare grew so malevolent that Kusla staggered back. "You dare!" it hissed. The voice had already been terrifying, but now, it seemed to shriek, its words filling the world.
"So not a real eye. Just an image. Just something from our minds" said the Doctor. "Do you have any physical presence here, or is this just something on the..."
Something seized him. The Doctor grabbed at what held his neck, but there was nothing there.
Kusla tried to move forward, but something held her as well.
"Those invisible beings..." she choked.
The Eye was looking down at them with delight. "They were once cultists, the first. But now, they do not exist in the world you see."
The Doctor could feel their presence, could feel the concentrated power of the eye. The very world, he realized now, reeked of the Eye's presence. It had the potential to see anywhere, but now its gaze was here. And the very air of the world was saturated with its malevolent gaze.
He twisted around, and grabbed the goggles, which had fallen from his grip when he was seized. He focused telepathically, and could see the creature. Its presence shifted, a face that was barely there, with eyes torn out, but one, terrible eye glaring at him. The Doctor struck at the creature, and somehow, now that he could see them, the blow seemed to connect.
The Doctor glanced around and saw Kusla, still trying to fight off whatever was holding her. He saw another of the invisible enemies strangling her. He threw her the goggles.
"Put them on!" he choked at her. "Just fight what you see!"
Gasping, Kusla put them on, she was barely conscious. She struck at something fiercely, and staggered up.
The Doctor, despite his system, doubted he could stand much of this. He could hear the blood roaring, darkness was growing around him.
Kusla ran back at him, wearing the goggles and struck at the air. The grip lessened, and as Kusla hit again, stopped.
The Eye glared at them. "You cannot hide from me."
"Perhaps. But... we can run" smiled the Doctor, doing so with Kusla.
"Did you learn anything useful? Worth us almost getting strangled?"
"Yes. The Eye isn't truly here. It's power is based on illusion."
They had reached the TARDIS.
They entered, the Doctor closed the doors and pulled a lever. "I've put us in orbital drift, it shouldn't be able to focus on us."
"Illusion... so what does this mean?"
"That the Eye isn't fully stabilized here. It doesn't have enough force to bring itself through fully. But if it gets to your world it could gain a power-base there."
"You've encountered creatures like this before?"
"A few times. Basically... it's relying on the mental energy of those who have joined its cult. It's more powerful in a climate of worshipers, due to their mental energy. That enables it to send out the invisible assassins. It can probably only observe other places... only interact gradually. Somehow it gained a foothold on this world, and now rules this area."
"How certain are you of this?"
"Well... this is partially guesswork" said the Doctor.
"And it wants to get to my world."
"Well it can't get people..."
Kusla suddenly looked worried. "My ship!"
"Well hopefully it's locked" said the Doctor.
"Yes, but... if they include people from my world, they'll know how to get past the lock in a day."