With no people around, the Ethereal had room to come out.

It was the year everything changed. Most other people had to stay in, but I was allowed out. I was a Key Worker and allowed to breathe the air, but I don't remember what exactly I did at the time. Maybe I just don't want to remember.

The first time I saw the Ethereal was the 0652 into Charing Cross. The train was empty; even the announcements had been turned off since every station had become a request stop. I'd sat next to the window in a group of four facing seats that would have been uncomfortably squashed during a normal rush hour. I had planned to listen to a podcast that morning, but I'd finished my last one shortly after boarding and was now just listening to silence with my headphones still on, staring out the window to my right as the empty streets swept past below.

A couple of bursts of static came through my headphones, shaking me out of my contemplation. I took the headphones off and had a look at them, as if that would tell me the source of the malfunction. Finding nothing, I put them back in my bag, and sanitised my hands afterwards.

"Sorry. Don't mind us. Hadn't realised there was anyone here."

It was like a whisper in my ear, sending a tingle down through my back and chest, quiet enough to hear it clearly but not loud enough to make me jump. I looked up.

You know that effect in Star Wars where a hologram gets disrupted and skewed, breaking down into static? They looked a bit like that to me. Sitting next to each other on the two seats facing mine. Two figures, just clear enough at times to make out some of their features, but transparent, out of focus. Shimmering.

They both had long hair, though the one on the left was dark and curly while the one on the right was bleached a lighter colour and straightened. They both wore simple t-shirts and jeans, which struck me as odd for beings that looked like they could be spirits. No colour in either, just varying brightness of the seats they sat on, showing through their bodies.

"Usually we can sense the mental activity, but I suppose you were meditating," the left one said. They looked like they were speaking aloud, but their voice still sounded like a whisper inside my mind.

"Um. Yeah. I was tuned out a bit," I replied. What else would you say when being greeted by ghosts?

"We're not ghosts," said Right. They chuckled. It sounded like a breeze through wind chimes. "Not as you understand ghosts, anyway."

"Hey now," said Left, looking at Right. "The Real don't like us reading their minds."

"Oh, yes, sorry," said Right, looking back to me. "I try not to. But you're freaked out. Your brain was yelling quite loud. Besides, I thought the same thing when I first saw myself."

Perhaps it wasn't just the whispering that was making the hair on my neck stand up. The whole exchange felt surreal, and I wasn't entirely sure I wasn't dreaming.

"Where are you travelling to?" I asked. Look, I was British. I wasn't going to ask such personal questions as "why are you translucent and are you figures of my subconsciousness?"

"Oh, all the way through London," Left said. "I suppose you're getting off at Charing Cross, though."

"Charing Cross is the terminus," I said, puzzled. The tracks stopped there, after all.

"This one's cute," Right said to Left, keeping their eyes on me and raising an eye playfully.

Left sighed at their companion. "We're what you might call the Ethereal," they said. "We're every present that may have been."

"I think you may like it where we're going," said Right. "The Event didn't happen in our place. Many events didn't happen. They're all around you, every day. Buildings that were never built. People that could never have been. Histories built upon histories. But you Real never usually notice them. The only thing that's real for you is your own timeline. You have no time for other timelines," they grinned at their own wordplay.

"You'd been rehearsing that one, hadn't you?" said Left.

Right ignored them. "I remember my Real form, before I split. It was very restrictive. But now I'm free."

Left rolled their eyes, a gesture barely noticeable given the poor lucidity of their image. "My friend loves to get poetic," they said. "Especially when flirting."

"I am not," Right protested.

"You know we're like ASMR to them," Left scolded them, though a smile crept onto their face.

"Oh, shush."

We'd just gone through London Bridge station, the empty Shard behind me to my left. The Ethereal could see it behind me, sitting on the backward-facing seats as they were.

"Okay, look", said Left. I shifted around in my seat to look to where they were pointing. It was a clear day, and the sun was reflecting off the glass surface of the skyscraper. I shielded my face as a ray of light momentarily blinded me.

"Ack," I grumbled. "The sun reflected right into my eye."

"Yes, quickly," said Left with some urgency. "Look out your window."

I turned back around to look. We were passing the Menier Chocolate Factory, which once a real factory but is now a theatre. Then I felt a tingle on my shoulder. I looked around and Right had stood up and placed a hand on my shoulder. The sensation was like cold pins and needles. "No, look," they said.

I turned my head back as the chocolate factory went past. And I saw, through the sun spots in my vision, there was smoke pouring out of the chimneys there, and pulleys hoisting carts of barrels and crates up into the goods windows from below. Then I blinked and the sunspots went and the factory was out of sight as the train continued on its way.

"What was that?"

"With no sensory input you were able to see the Ethereal," Right said, removing their hand after a slight hesitation. "The chocolate factory is still a chocolate factory in a lot of phases. Perhaps we could visit it with you sometime."

"Hey!" Left scolded Right. "Stop tempting the poor thing."

"I'm not…," I said. Right "Do you mean I can—the Real can—get to see this without, uh, help from you?"

Left hesitated. "Yes and no. We can help you become part of the Ether, but it would require leaving the Real plane. We're in the middle of another phase shift, and that's when alternative histories are created, and when we can visit back here for a bit. It's good. It helps clear the muddle of many timelines stacked onto each other."

"So I'd be giving up my life here?"

"Sort of. You'll split into two parts, the Real and the Ethereal. Your Real body will continue here as you would do, and appear normal to everyone, but would no longer have conscious continuity for you. Your consciousness would become Ethereal and you would exist in the many planes like us.

"And there's some pretty good planes," Right said. "I like the one where London never developed. All this is marshland, it's beautiful."

We were coming up to Waterloo East station.

"How would I do it if I decided to?" I asked.

Left gave me a sad look. "I don't think you understand," they said. "The phase shift finishes soon. Very soon. This train in our phase carries on through Charing Cross, underground through London, just in time before the shift ends. We would help you, but you'd have to decide in the next couple of minutes."

It's strange how the immediate need to make a decision can focus one's mind. Things were not easy in the Real world right now. By most accounts, things were likely to get worse still. But it was Real. It wasn't floating through dimensions, trying to stay grounded by returning here on occasion, visiting reality like a tourist.

Was it okay to bail out when things were hard? Supposedly nobody would notice, but I would know. Drifting through every alternative history, perhaps enjoying myself, while my body continued with its Key Work and everyone else suffered? Could I do that?

Or was it foolish to pass up an opportunity like this? Doctor Who has landed and their TARDIS is waiting to take you anywhere you could imagine. Who would blame you for going with them?

A couple of wheel screeches and the familiar rumble of the train crossing Hungerford Bridge on its final approach into Charing Cross.

"I … can't go. It wouldn't be fair on everyone else. I know nobody would know, but I feel that if they did, they would judge me harshly."

Left and Right nodded. "I had a feeling you would say that," Right said. "Just remember for your future that people think badly of you less than you think."

"Will you ever be back?"

"Yes, probably, the next time there's a phase shift. There's a lot happening right now. Once or twice a year at the moment. We see you every time, and wondered if you were ready, but we didn't think you were then and it seems like you're still not yet."

"We will look out for you."

"What are your names? I never thought to say. I'm Robin."

"We're also Robin," said Left, smiling knowingly. "I'm the you who adopted a cat when you were 15."

"I'm the you who took a risk that first evening at university," said Right.

I nodded. There didn't seem to be anything worth saying to that, and certainly not enough time to begin to dwell on it yet. Every decision I'd made and that person existed out there. It was comforting in a way. There were no bad decisions, just different people living out the consequences.

The train stopped and the door opened. I stood up, as did the other two. Right put their hand on my shoulder again, imparting that electric sensation again. "So you can see us off," they said.

I alighted the train and, my shoulder still tingling, closed my eyes.

The Ethereal train appeared in my vision in place of the Real train. My other selves waved to me from the doorway as the sliding doors closed in front of them. With a familiar hum of the electric engines, the train started moving again, heading down into the tunnel portal that didn't exist in the middle of the Charing Cross concourse.

While the immediate need to make a decision can force one's mind towards one direction, the feeling after it's been made and can't be changed will confirm if you made the right one.

And as they disappeared out of sight, I knew, while I was needed here for now, that should they appear to me again then I would go with them.