ave I mentioned before that every day, we each have 70,000 thoughts? Well, we do.

That’s 3,000 thoughts per hour, fifty a minute, or just under one contemplation per second.

But some of them are of greater quality than others.

I think this is my best one yet.

“Nat,” I breathe as the one hundred trillion synapses in my brain start firing simultaneously, “look.”

It’s like spending days and days trying to finish a difficult jigsaw puzzle, then finding that the one piece you need has been stuck to the bottom of your foot the whole time.

Or – you know.

Another analogy that doesn’t make it sound like I don’t shower.

One day I am hoping I will be in romantic twosome too, Harry-chan.

I have that once. And now I am a bit … contusion.

Rin wasn’t trying to say confusion at all: she was trying to say bruised.

She’s not just homesick, she’s crushed.

My friend has wanted to be part of a big love story as long as I’ve known her, but her very first tentative attempt ended in immediate rejection. And OK, last year she specifically said she wanted an Australian boyfriend, but … (shut up, box) I don’t know any of those any more.

But Team JINTH need to drag this particular princess out of her tower for good.

Maybe a British prince will do instead.

“I’m looking,” Nat sighs impatiently, picking a leaf out of her hair. “Why are we in a bush? And by the way, was your cat wearing fake pigtails?”

“Sssshhh,” I whisper, mentally turning the final piece of the puzzle round and round until it fits. “I’m still thinking.”

Jasper’s usually so sarcastic about everything, and yet here he is: patiently looking through photos of a black cat wearing a white catsuit without a single sardonic comment.

Not one snip; not a derisive or scornful snort. Not a contemptuous observation or a caustic reflection: not even a scathing expression.

Just sweet, genuine interest.

In Year Five, we did a basic experiment with magnets and we learned that the south pole of one magnet is attracted to the north pole of the other. (And then Nat and I used this knowledge to clip our magnets to the end of our noses.)

i.e. We learnt that opposites attract.

And the law of electromagnetic nature seems to be at work here too.

I narrow my eyes analytically. I tell everybody constantly that science can be practically used in everyday situations, and this is the perfect example.

Rin’s sweetness balances out Jasper’s sharpness; her sugariness is the perfect counterpart to his bluntness. They even look good together: he’s broad and tall and wearing dark grey, and she’s tiny and dainty and pastel-coloured like a butterfly.

Despite their differences, they’re a perfect match.

Actually, no: because of them.

“Seriously, Harriet,” Nat says, “these are brand-new Seven jeans and now I’ve got mud on the … Oh my God.”

I beam at her. I knew she’d catch up eventually: I just had to wait for our magical best-friend telepathy to do its thing.

“Right?” I say triumphantly. “Can you see it too?”

We look back at the bench.

Jasper’s genuinely not scowling for the first time in ages: he seems lighter. Happier.

“Huh.” Nat looks at me, visibly impressed. “You know, I can’t believe this, Harriet, but you’re right. Those two are made for each other. How did I not spot this before you?”

“Experience,” I say, nodding sagely. “I am wise and learned, Nat. Like Yoda, but with a better grasp of sentence construction.”

“Like guru, you are.”

We laugh and look back at the sweet little scene playing out in front of us. The rebellious box in my head is starting to rattle uncomfortably, but I don’t really have a choice. I’d locked everything away tightly for myself … but maybe I need to open the lid a tiny bit, just to make sure my new plan works.

Just a couple of centimetres.

Enough to get a smidgen of what I know about romance out, make two of my best friends so much happier than they were and then put it away again. Like a handyman delicately picking the best tools out without touching the chainsaw.

Yes: I think that’s perfectly safe.

As long as I’m super careful.

“I’m going to do it,” I say decisively. “I’m going to get them together.”

“Wait.” Nat looks at me in alarm. “Hang on, Harriet. Why can’t you just let it happen naturally?”

“Because we don’t have time,” I explain. “The chemistry’s there: I just need to speed it up a bit. I’m the catalyst, like iron when used in the synthesis of ammonia from nitrogen and hydrogen. I’m not changing the future, just making it get here faster.”

“But Harriet …”

“Don’t worry,” I say reassuringly, standing up and pulling a twig out of my fringe. “I know exactly what I’m doing. Everything is under control.”