"So, what am I looking at?" Clara's palms are pressed against a standing stone, several feet taller than she. The rock feels rough, warm under her palms. Six sister stones are arranged in a circle, their feet still shod in unexcavated soil.

"It's a Ri'Jinn stone circle. Commonly found throughout their home star system."

"Hmm. Which is several million light years from here."

"That's why it caught my attention," smiles River.

"What do they do?"

"Historically they're thought to be calendars. Counting down to Circle Time. Ri'Jinn religion is complicated, but they believe at certain times and places the Universe is thin enough to pass through. Into a place outside of the normal flow of time."

"Is that true?"

River shrugs. "Perhaps. All the previous circles I've excavated had run out of time. The dates they referred to had passed." She taps a complicated iconography scratched into the stone, incomprehensible to Clara without TARDIS translation.

"But not this one?"

"No. It's counting down."

"I assume there's a reason you haven't taken a TARDIS to the right date and seen for yourself what it does?"

River smiles again. "Proximity to time travelling ships stops the countdown."

"How? How can a set of stones know that?"

"The last research team that tried to find out suggested they were receptive to Artron energy..."

"Tried?"

"Their entire lab was destroyed in a huge explosion. No survivors."

"Oh good." She releases the stone at last, and follows River away from the dig site. There is a tent pitched between the trunks of tall pines that surround the circle. "Is that all the bad news?"

"Apparently a sizable portion of the Ri'Jinn fleet entered hyperspace a week ago."

"Which means, if they're heading here, they could appear within the next forty-eight hours. Just a wild guess, but is the countdown for the circle due to end in that time?"

"Yes."

Clara screws up her face. "Of course. Well, we could use the TARDISes to set up false Artron signatures to lead them astray. Maybe buy enough time for some of us to go through." She catches River's expression and sighs. "What else?"

"Vastra and Jenny have a commitment to history to keep. They already know too much about what's happening here for the timeline to be safe. They can't spend forever looking for the Doctor. Not with Strax at home looking after their investigations."

"And Missy and Lady Me will need to pilot the TARDISes. So, it's a two-woman mission then." A smile tugs at the corner of her mouth. "That's pretty much how I roll."

"I can't come with you."

"What? Why?"

"Not enough pages left in my diary."

"Oh, come on. You're not staying behind because of a stationery crisis. That's the most ridiculous—"

"The Doctor gave me this," River continues, producing the battered volume from her bag. "He's the kind of man who would know how many pages it would need. We can't all cheat death."

Clara flinches at that, biting her lip for a moment. "We cheat death all the time. Even if it's a fixed point, there's no saying—"

"My decision is made."

Brown eyes meet blue for a long moment, until eventually Clara nods. She leaves the archaeologist under the fragrant pines, trudging on to where the shuttle is parked.

Me is waiting for her when she returns to orbit, curled like a cat in a yellow button-backed armchair she has installed in the console room.

"You've redecorated," says her former companion.

"So many happy memories associated with that old desktop," Clara quips, "why wouldn't I keep it?" She pinches the bridge of her nose. "Sorry."

"It's okay."

"No, there's no need for me to be so rude."

"You're still angry."

"I need longer," she nods. The tick and hum of her ship is reassuring under her hands as she leans back against the console. Going to miss this, she thinks. "To forgive—"

"And I to forget," finishes Me, rising from her chair. Her fingers catch Clara under the chin, raising her face gently to meet the immortal's steady gaze. "Time heals all wounds. Eventually."

"So I've been told." Clara turns away, flicking switches pointlessly, until the lump in her throat is swallowed. "Anyway. How do you feel about driving the old man again?"

"I'm looking forward to it. A challenge to keep out of range of Ri'Jinn weaponry."

"I want him back without a scratch on him," she replies, mock-stern, then chuckles. "Come on. I could do with a hand packing, if you're willing to help?"

"Always," Me replies, smiling sadly.