Thirteen years after he left, my ex-husband asked me how I dared show my face at that competition. His own sons were standing six feet behind me and he looked straight through them.

PART 1 — THE FOYER

Dom left in the March of 2012 for a woman called Simone and the boys were three.

Thirteen years later he stood in the foyer of the Ardwell University auditorium and said, at a volume that reached the registration queue:

"How have you got the nerve to show up here?"

I am forty-five. I had spent about a decade telling myself that the sound of that man's voice had stopped doing anything to me.

It had not. My hands went before my face did.

He was in a navy shirt that had been pressed by somebody. Simone was on his left in a good coat.

And on his right was Caspar, sixteen, in a private school blazer, holding a leather folder flat against his chest with both hands.

Simone did me from the shoes up. The flats, the beige jacket, the clear plastic wallet under my arm.

"Greer," Dom said, as though the name had gone off. "What are you doing here?"

First time he had spoken to me directly since 2012.

"I'm here for the competition."

Simone came half a step forward. "It's a private academic showcase. It's invitation only."

"It's the regional STEM championship," I said. "State and independent qualifiers both."

His face did the thing.

Three or four parents in that queue had stopped pretending not to listen.

"Don't," he said, lower. "This weekend matters for Caspar."

And behind me were Rory and Felix.

My sons. His sons.

Sixteen, both of them about an inch off him now, with the same habit he has of going very still and watching a room when something uncomfortable starts.

Grey hoodies with nothing on them. Contestant badges round their necks. Rucksacks with straps I have restitched twice because there is nothing wrong with the rest of the bag.

Dom looked straight at them.

And he did not know them.

I have gone over why that was the worst part and I have got nowhere, except that it is.

Thirteen years of birthdays and sports days and two in the morning with a thermometer. Circuit boards on a kitchen table that wobbles. School fairs in hot classrooms with eleven parents in them.

He stopped ringing a long time before they stopped asking when he would.

And he was standing six feet from them and he did not know.

I said: "I'm here for my sons."

And Dom laughed. One of those.

"Your sons?"

His eyes went over the two of them and came back to me with nothing in them at all.

"Yes."

And Simone folded her arms and said: "Well. I hope they haven't come expecting much. Caspar's had six months with tutors from the department."

I did not say anything to that.

In my wallet were two registration receipts, two preliminary score sheets, and a photograph from 2021 of the twins over our dining table building something out of a dead PC.

I had brought it and I did not know why. A mother's version of a lucky pen, probably.

Felix came up next to me.

"Mum. Registration shuts in ten."

"You're right."

There is a thing I did in that foyer that nobody saw and that I have not been able to let go of.

When he said your sons? and laughed — I did not turn round.

I had two sixteen-year-olds standing six feet behind me and their father had just laughed at the idea of them existing, and I kept my eyes on him.

Because I did not want to see their faces.

That is the honest version. Not to protect them. I did not want to know what was happening on my own children's faces at that moment, because if I had seen it I would not have been able to get through registration.

Rory has told me since that nothing was happening on his face.

And Felix has told me, separately, in the car, about a month later, that he had already worked out it was him before we got to the doors — from a photograph on the university's parents' page — and that he had decided on the walk from the car park not to say anything to me.

So both of my sons spent that foyer managing me.

And I walked past Dominic Hallam.

"Greer," he said.

I stopped.

"Don't make this about us."

And I looked at that man properly for the first time in thirteen years, and I said:

"I didn't come here about us."

And the thing I remember is that there was nothing underneath it. No edge. I have waited thirteen years to say something to that man and when it came out it was just a fact.

PART 2 — THE ENVELOPE

Inside, the walls were boards. Equations, robotics builds, a thing about materials I did not understand one word of.

When we were far enough off, Felix said: "Mum. That was him."

I did not do the face.

"Yes."

And Rory said: "Our dad."

"Yes."

Neither of them said anything for a bit.

Then Felix straightened his badge and said: "Okay."

That was it. No questions. They went off to their tables.

The preliminaries went nearly three hours. Logic problems, applied physics, and then a technical defence in front of a panel.

I sat at the back with a coffee going cold and watched my sons do the thing they have done since they were about nine, which is argue quietly and correct each other without either of them minding.

At lunch I saw Dom across the concourse with a group of parents, being extremely good at that, which he always was.

Caspar was next to him and he did not look right. He was holding that folder the same way he had held it in the foyer and he was not eating.

And I did not enjoy that. I want it down, because people assume. He is sixteen and he is standing inside somebody else's expectations.

The finalists went up at twelve.

Caspar qualified. Rory qualified. Felix qualified.

Dom was about four yards from that board and I do not believe he read the state-school lists at all.

The final defence finished at about five and that auditorium was full for the prizes.

Simone had two seats in the third row, on the aisle, where you can be seen.

We were further back, near the middle.

Professor Ozturk did the commendations, then bronze, then silver.

And then she picked up an envelope and said:

"This year, for the first time in the recent history of this championship, the highest cumulative score is an exact tie — between two competitors from the same school."

Rory took my hand. Felix stopped breathing.

In the third row Dom sat up and did his jacket.

And Professor Ozturk opened that envelope and read out two names, and they were both mine.

I am not going to try to describe the next bit because I was not in a fit state to record it.

What I have is what other people have told me.

They went up together. They did not look at the third row once, either of them, and that was not a decision, because I asked them both afterwards and neither of them had thought about it.

And Dominic Hallam stood up in the third row.

Not to clap. He stood up and he stayed standing, in the middle of a row, while four hundred people were sitting down around him, and Simone pulled at his sleeve twice.

He was reading the surname on the screen.

Lisk. Not Hallam. I changed back in 2014 and I changed theirs in 2015 and there was a process and he was served and he did not respond to any of it.

He was standing in that row working out the maths on two boys he had looked at in a foyer four hours earlier.

Simone got him sat down. It took her about nine seconds and she did it without a word, two pulls on the sleeve and then a hand flat on his forearm, which is a thing you learn to do over years.

And then I did something I am not pleased about and am not going to leave out.

I watched him for the rest of that ceremony.

There were two more awards and a closing speech of about six minutes and I did not look at the stage once. My own sons were up there having the best day of their lives and I spent it looking at the back of a man's head in the third row.

I have been doing that for thirteen years, is the thing. Not his head. The space where he should have been.

Every sports day. Every parents' evening. I have never once gone into a hall and not clocked that there was one of me.

PART 3 — FOURTEEN MONTHS

Caspar came and found them afterwards.

Not in the hall. In the corridor by the vending machines, about twenty minutes later, while I was holding three coats.

And he did not do what a boy does when he is meeting somebody.

He said: "Rory. Fee."

Fee. Nobody calls Felix that except his brother and my sister.

And I stood there with three coats over my arm and watched my sixteen-year-old stepson-who-is-not-my-stepson use my son's family name for him in a corridor.

They have known each other for fourteen months.

Not in person. That was the first time any of them had been in a room together.

It started on a build forum. One of about nine places those two live. Caspar was posting under a handle and so were they, and they got talking because of a servo problem, which Rory has since tried to explain to me twice.

And about six weeks in, Caspar worked it out.

He did it the way a sixteen-year-old does, which is that somebody posted a photograph of a workbench with a window behind it and he recognised the road.

He had been driven past our road. Twice, he says, years ago, in a car, with his mother.

And then he found a surname and a town and he sat with it.

He did not tell them for about a month.

Rory has described that month to me. Caspar went quiet in the thread for nine days and then came back and carried on about the servo as though nothing had happened, and Rory thought he had gone off it.

What he was actually doing, on his own, at fifteen, was deciding whether to say it.

He has told me he wrote the message four times.

Then he did, in a message, and Rory has shown me that message with Caspar's permission, and it is four lines long and the last one is: I don't want anything. I just didn't want to know it and not say. Then he did, in a message, and Rory has shown me that message with Caspar's permission, and it is four lines long and the last one is: I don't want anything. I just didn't want to know it and not say.

Fourteen months.

They talk most days. They have built two things together, remotely, which I have had explained to me and which I still do not fully understand.

And nobody told a single adult.

Not his parents. Not me.

And on the fourteenth of January this year, Caspar Hallam sent my sons the entry link for the Ardwell championship.

They had not heard of it. We are a state school and that competition was not on anybody's radar at theirs, and the entry window was eleven days.

He sent them the link, and then he sent them four months of past papers that he had off his tutors.

The boy with six months of departmental tutoring sent his tutoring to the two people he was going to be competing against.

I asked him why, in my own kitchen, in the February, with his mother's permission and a lot of forms.

And Caspar said: "Because he'd have to look at them."

I asked him whether he had thought about what would happen if they beat him.

And he said yes. He said it immediately, no pause at all.

And then he said: "They were always going to."

He had known that since about the April. He had been sending past papers to two boys he had already worked out were better than him, for nine months, with a view to standing in a hall while they proved it in front of his father.

I asked him one more thing, which I had not planned.

I asked whether he had ever considered just telling his dad.

And Caspar Hallam said: "I did. In Year Nine. He said I'd got it wrong."

He had gone to his father at fourteen and said he thought he had brothers.

And Dom told him he was mistaken, and that was the end of it, and that boy carried it on his own for another two years.

PART 4 — SEPTEMBER

Now mine.

I knew. Not for fourteen months. For about five.

The Sunday before that, I had a chance and I missed it, and I did not understand what I was being given.

Felix asked me, out of nothing, while I was doing the washing-up, whether I had any photographs of Dad.

Not angrily. Just a question, from a boy drying a pan.

And I said: "Somewhere, probably."

And he said okay and carried on drying.

He was asking. That was him asking, at sixteen, after six years of nothing, and he had worked up to it, and I gave him somewhere, probably over a sink.

Five days later I was doing something on Rory's laptop — printing a form, with his permission, he was in the room — and a message came up across the top of the screen.

It was from an account called cas_h and it said something about a bracket.

And I said, "Who's Cas?"

And my son went a particular colour and said: "A lad off the forum."

And I knew. I cannot tell you how and I knew in about a second and a half, and I think it was the H.

I did not shout. I have never shouted at those two in my life.

What I did was worse and it took me three days.

I waited until the Sunday and I sat both of them down at that table and I said I knew who Cas was, and that I was not angry, and then I said the thing.

I said: "I'd like you to leave it, boys."

And Rory said why.

And I said — and I have had to repeat this sentence out loud in a room since, which is its own kind of punishment —

"Because nothing good has ever come out of that house and I'm not having it start now."

That house. Meaning a sixteen-year-old.

Felix did not say anything. Rory said all right, Mum.

And then they did not leave it. They carried on, every day, for five months, and in the January they entered a competition on his say-so and told me it was a thing their physics teacher had mentioned.

They lied to me for five months.

And when I found that out, in that corridor by the vending machines, the thing that went through me was not anger.

It was: of course they did.

There is a second part to the September and it is worse than the sentence.

After I said it, Rory asked me one question.

He said: "Does he know about us?"

Not does Caspar. Does he. Meaning his father.

And I said I didn't know.

Which was true. I did not know. Dom had not been told by me since 2014 and I had no idea what that house contained.

And then my son said: "Could you ask?"

Eleven words, at a kitchen table, from a sixteen-year-old who had just been told to drop the only link he had.

And I said: "I'm not ringing that man, love."

That is the end of that conversation and that is the last time either of them raised their father with me before the twelfth of April.

Five months. And then a corridor by a vending machine.

PART 5 — THE PHOTOGRAPH

Because of a lunch in 2020.

My sister Bets does a thing every August at hers and there are about twenty-five of us in that garden.

The twins were eleven.

And Rory had been in the house on Bets's computer and he had printed something out and he brought it out to the table folded up in his hand.

It was a photograph of Dom off a company website. A headshot. Shirt and a background.

He was not upset. He was eleven and he was showing my sister's husband, the way you show somebody a thing you have found.

And I came round that table and took it out of his hand.

"Give me that, love. Not today."

And then, folding it, to everybody: "Put it away. We're not doing him at your auntie's. Go and get some cake."

My brother-in-law said something about me being quite right.

Somebody laughed. Not unkindly — the way a table laughs when somebody has handled a small awkward thing well.

That is what I had done, as far as that garden was concerned. I had handled it.

Bets got up and went in for the cake, and she has told me since that she went in because she did not want to be in that garden for the next minute, and that she stood in her own kitchen with the cake for a bit.

She has also told me that Felix watched me put it in my bag.

I did not see that. Bets did, from the back door, and she has had it for five years and only gave it to me in the May because I asked her, directly, what she remembered about that afternoon.

Felix was eleven and he watched his mother put his father's face into a handbag, and then he came and had some cake.

And my son said okay and went and had some cake.

I put that photograph in my bag. It is in a drawer in my room and it has been there since the August of 2020 and I have looked at it twice.

Eleven years old, and what he learned at that table in front of twenty-five people is that his father is a thing you do not bring out where Mum can see.

Five years later a boy on a forum turned out to be his brother, and my sons went and got on with it on their own for fourteen months.

They did not keep it from me because they are sly. They kept it from me because I taught them to, in a garden, with cake.

And I have thought about the other thing in that sentence, which is that I did not teach them to lie about their father.

I taught them that their mother could not survive hearing about him.

That is a different lesson and it is the one that took. For five years those two have been carrying a thing round the house that they believed would go off if they put it down in front of me, and they were right, because in the September I proved it.

I have said all of this out loud to a woman in a room in Ardwell on a Wednesday afternoon, twice now, and both times I have got stuck in the same place.

Which is that from the outside I did everything.

Thirteen years, two jobs for six of them, never once said a bad word about that man in front of them, never asked them to pick.

Never said a bad word. I just removed him, quietly, every time he came up, and called it protecting them.

Where it is now.

Caspar comes on a Saturday about once a fortnight. That took four months, two meetings with Simone that I would not describe as warm, and a lot of care from people better at it than me.

Simone has been the surprise of my life. She did not know either. She found out in that corridor the same as I did, and she rang me on the Monday, and she said one sentence I will keep: "I'm not going to stop him. He hasn't done anything wrong."

Dom has rung three times. The boys have not answered and that is theirs and I have stayed out of it entirely, which has taken more than anything else in this.

The twins start at Ardwell in the September, both of them, on the scholarship that came with that envelope.

And there is a photograph on my wall now that is not the one in the drawer.

It is the two of them on that stage with Professor Ozturk, taken by a parent I have never met, who found me on the school page afterwards and sent it.

In the bottom left corner of it, out of focus, in the third row, there is a man standing up in a row of people who are sitting down.