I feel a surge of hatred that’s a bit like bile but manage to suppress it under a smile.

“So!” I greet her. “Demeter! Welcome to our bespoke nature walk. We’ll head up into the woods, stretch our legs, and see a huge variety of wildlife. Sound good?”

“Well, all right.” Demeter looks a bit unconvinced. “Is there a lot to see in the woods?”

“Oh yes,” I say, with a bland smile. “Don’t worry. You won’t be bored. Do you have sunscreen on?” I add. “It’s hot today.”

It’s not just hot, it’s baking. Biddy slathered all the children with sunscreen earlier on, and she’s made some ice lollies, which will be ready for lunchtime.

“I’m wearing factor fifty, actually,” says Demeter smugly. “I use this wonderful brand which I get at Space NK; it has neroli oil and argan milk—”

“Great,” I cut her off before she can do my head in with her boasting. “Let’s start, then.”

I only mentioned sunscreen to sound professional. Where Demeter’s going, she won’t need sunscreen. Mwah-ha-ha-ha.

I lead the way briskly across the fields, the blood pumping through my veins. I’m a little hyper this morning. I woke at 5:00 A.M., fully alert, my head already full of Demeter.

And Alex. Both, I suppose.

OK, full disclosure: My head was actually full of Alex, with Demeter popping in for the odd cameo. Which is ridiculous. This is a guy I met a handful of times. A guy who’ll have already forgotten I exist. Why should he have got inside my brain? Why should I feel so…what, exactly?

Betrayed. That’s what I feel, I realize. I feel betrayed that he should go for someone like Demeter, who’s so married, so inappropriate, so Demeter-ish. When he could have had—

Well. All right. Before I sound totally tragic, here’s the thing. I’m not just saying, Oh, I wish he’d fallen in love with meeee….I mean, obviously I do wish that, kind of. But it’s bigger than that. It’s like: Are you really a Demeter person, Alex? Because I can’t see it. She doesn’t have your humor. She doesn’t have your flippant airiness, your live-wire irreverence. I can’t see the pair of you gelling, I just can’t, I can’t, I can’t…

“Sorry?” says Demeter, and I realize I’m muttering, “I can’t,” under my breath.

“Just doing a Vedari chant,” I say hastily. “Helps me focus. Now, keep your eyes peeled for voles.”

“Voles!” exclaims Demeter.

“They’re tiny creatures, rather like mice, but much more special.” I nod. “And there are stacks of them in this field.”

There’s no chance that she’ll catch sight of a vole, but at least it’ll keep her off my case for a bit. Sure enough, we walk on in silence, Demeter determinedly scanning the ground.

“So!” As we arrive at the edge of the woods, I turn like a tour leader. “Welcome to Ansters Woods. In here we’ll find a biodiverse world of animals, plants, and even fish, all working together in harmony.”

“Fish?” queries Demeter, and I nod.

“There are streams and ponds in the woods which are home to several very rare species.”

Which is, you know. Probably true. Whatever.

I’ve deliberately headed toward the thickest, most tangled part of the wood, and Demeter’s eyeing the brambles nervously. Well, what an idiot she is, wearing shorts.

“Ow!” Demeter’s voice suddenly rings out. “I’ve been stung by a nettle!”

“Bad luck,” I say blandly. As we walk on, I can’t help adding, “The trick with nettles is to grasp them. Grasp the nettle and everything will be OK. Don’t you agree?”

I can’t tell if Demeter gets the reference or not. She’s staring at the overgrown path ahead and seems unnerved.

“Don’t worry,” I say reassuringly. “I’ll cut us through the undergrowth. Keep close behind me and that way you’ll find it easier.”

I take a long, whippy stick and start slashing through the bushes, accidentally on purpose using such a vigorous, wheeling motion that I catch Demeter on the leg too.

“Ow!” she says.

“Oh, sorry,” I say in an innocent tone. “I totally didn’t mean to do that. Let’s carry on. Look around and you’ll see birch, ash, and sycamore trees, as well as oaks.” I give her about thirty seconds to peer at the trees, then continue: “So, what are you up to tonight, Demeter? It’s just you and the kids, isn’t it? You must be feeling so sad that your husband’s gone. So lonely, all alone in your yurt. Just you, no one else.”

As I speak, I feel resentment simmering. Look at her, in her denim shorts, catching some sun, revving up for a night of torrid sex.

“I know; it’s a shame. Just one of those things,” says Demeter with a shrug. She’s peering at the trees around us. “So, which is the sycamore?”

“I mean, you came here as a family.” I smile so hard, my cheeks start to tremble. “With your lovely husband who you made those special vows to. How long have you been married?”

“What?” Demeter looks puzzled. “Um…eighteen years. No, nineteen.”

“Nineteen years! Congratulations! You must really, really love him!”

“Er…yes,” says Demeter, looking bemused. “I mean, we have our ups and downs….”

“Of course you do. Don’t we all?” I give a shrill laugh. All this time, I’ve managed to keep outwardly calm around Demeter. But today I’m losing it a bit.

“So are there many interesting bird species in the woods?” asks Demeter, with her “alert and intelligent” expression that really rubs me the wrong way.

“Oh yes,” I say, breathing hard. “Definitely.” As a crow flutters out of a tree, I point upward. “Look! Did you see that?”

“No!” says Demeter, and immediately cranes upward too. “What was it?”

“A very rare bird,” I say. “Very rare indeed. The great crested…boaster.”

I nearly said, The great crested Demeter.

“It’s related to the warbler but much more rare,” I say. “Very predatory. Very toxic, nasty bird.”

“Really?” Demeter sounds fascinated.

“Oh yes.” I’m on a roll now. “It pushes the younger females out of the way and it won’t let them thrive. You wouldn’t want to come across it in the wild. It’s vicious. Selfish. I mean, it looks good. It has very sleek plumage. But it’s very crafty. Very pretentious.”

“How can a bird be pretentious?” Demeter sounds puzzled.

“It preens itself all the time,” I say after a pause. “And then it gouges out the other birds’ eyes.”

“Oh my God.” Demeter looks like she might be sick.

“Because it’s got to be top bird. It’s got to have everything. It doesn’t care if the other birds in the wood are struggling.” I pause. “But then, when it’s off guard and vulnerable, the other birds take revenge on it.”

“How?” Demeter looks utterly gripped.

“They have their means,” I say with a bland smile. I wait for Demeter to ask another question, but she doesn’t. Instead, she gives me a weird, appraising look.

“I was reading a book about local birds last night,” she says slowly. “It didn’t mention the great crested boaster.”

“Well, like I say, it’s very rare. One of our rarest. Shall we?”

I motion for us to carry on, but Demeter doesn’t follow. Her eyes are running over me as though for the first time. Oh God, she doesn’t suspect something, does she? Was the great crested boaster a step too far?

“Have you always lived in the country?” she asks.

“Oh yes!” I laugh, relieved to be on firmer ground. “I was born in the farmhouse,” I add, broadening my burr. “My dad’ll show you the marks on the kitchen wall, measuring my height over the years. This is home for me.”

“I see.” Demeter looks only partially reassured, but she starts following me again.

“You’ll want to see the ponds,” I tell her over my shoulder. “Beautiful wildlife at the ponds. We’ll go there now.”

They’re always called “the ponds,” but it’s one pond, really. One quite large, fairly deep pond and one shallower dip, right next to it, which is sometimes a pond and sometimes a swamp. At this time of year, it’s swamp. About three foot deep of swampy, froggy mud, all topped off with bright-green weed.

And that’s where Demeter’s heading, whether she knows it or not. I want her plastered in mud, dripping with weed, screaming with fury, and then—final touch—immortalized in a viral photo, which I’m sure Flora will have great pleasure in disseminating to the world. My phone’s in my pocket, covered in protective plastic. I’m all set. The only issue is going to be getting her into the swamp. But even if I have to dive in first myself, I’m doing it.

My breaths are coming fast as we walk along. My ears are buzzing; I’m twitching at every sound from the trees. Every so often, I have a spasm of nerves and think: Do I really want to do this?

Shall we just go back to the farmhouse instead?

But then I picture Demeter tapping at her phone with that smug smile, summoning Alex like a take-out order the minute her husband disappeared. Demeter making me do her roots…thrusting her Net-A-Porter boxes at me…complaining about her tiny journey to work…Demeter staring at me in the lift at Cooper Clemmow. She couldn’t even remember if she’d let me go, because, hey, what does the life of some junior girl sitting in the corner matter?

There I was feeling sorry for her—well, what a joke. She doesn’t need my pity. I mean, look at her. I glance at her long legs, clad in designer wellies. Her confident, I’m-the-boss stride. If she had a brief moment of vulnerability, it’s long passed now, and I was a mug to fall for it. Because Demeter’s always been an expert at using other people to sort her life out. Husband disappeared? Order in your lover instead. Deleted a crucial email? Get your assistant to sort it out. Somehow she always manages to come out on top.