Magic sense was what Regulus meant to teach.
At its simplest, it was an innate sense of magic, like sight or hearing. Most wizards never trained it deliberately, and while some awareness developed naturally with age and experience, its depth depended on talent.
At the lowest level, a wizard could only sense whether magic was present. At the highest, they could perceive how magic moved, where it gathered, what character it carried, and even the structure of a spell as it formed.
That ability was essential for advanced magic. Potioneers needed it to track magical changes as ingredients fused. Alchemists needed it to perceive the magic within materials. Gringotts curse-breakers relied on it to detect layered enchantments, while Aurors needed to read a spell's shape and direction before it was fully cast.
Most Pure-blood families taught magic sense eventually, as did some Half-blood families. Tradition usually meant waiting until a child's magic and mind had matured.
Cuthbert and Hermes would learn it eventually, and Alex probably would as well.
Lina and Samuel were different. Without Regulus, they would likely wait for their abilities to develop naturally.
Regulus disagreed with that approach. Magic sense, like magic control, was a foundation, and foundations were best built early.
Since the opportunity had presented itself, he would teach them.
He pulled his thoughts back and glanced round. Lina had a fistful of freshly picked moonlight moss.
Common enough stuff. A basic potion ingredient, useful for the calming draughts and healing salves brewed in first year, already obsolete by second.
Its magic was clean, steady, clear, uncomplicated. Nothing better for a young wizard to practice on.
The five of them stood in a half circle, watching him.
Regulus lifted his chin. "Lina. Hold it up."
She blinked, looked down, then raised the moss to her chest, cold white light washing up over her face.
"Nobody use their eyes."
His voice stayed low, and something else rode under it.
A gentle current of mental force spread out from him, carrying a soothing weight, level and quiet, drifting along with the words to press their excitement and fidgeting flat and settle them.
"Close your eyes. Touch it with your magic. It won't feel like touching anything else."
Their minds stood entirely open to him. The connection formed almost the instant he reached.
He took what his own senses held, the texture of the moss's magic, that cool thread of it, and pushed it down the link into their heads.
No method was less trouble. Better than a quarter hour of explaining what magic sense tasted like was letting them taste it.
The reason they couldn't find the door was that they didn't know what they were looking for. The faculty sat there unused, never once pointed in the right direction.
So he walked them through it once. Showed them what that cold white glow looked like from inside magic sense: light, faint, cool, and nothing at all like the stone and soil and dead leaves around it.
One delivery, one mouthful of the flavor, and next time they'd know where to reach.
The neglected sense, hooked that way, woke.
Hermes reacted first. His eyelids lifted, he gave the moss a look, shrugged, backed off a few steps and leaned against the trunk again, the whole performance saying it was nothing much.
He'd caught that cool taste at once and found it worthless. Whatever Regulus wanted him doing here ranked among the dullest things he could imagine.
Regulus flicked a glance at him.
The talent there was the highest of the five, the mental strength thicker than anyone else's. First to catch it, as expected of him.
But slow, patient work bored him witless. Occlumency was the same story. He practiced because Regulus told him to, and only once the stakes were spelled out did he put himself into it.
Regulus let it lie. Obedience was enough.
Cuthbert stirred next. Pure-blood breeding and no shortage of talent.
Eyes shut, brow faintly creased, then his eyes flew open and he looked down at the moss in Lina's hand with his whole face announcing that so this was magic sense, and it wasn't so mysterious after all.
He shuffled a step closer to her and poked a finger into the moss strands, discovering that texture under the skin and texture in the magic were two separate things. He poked it again.
Then he started sizing up the others, and after a couple of looks his mouth split into a grin.
Lina's reaction ran loudest. A small cry, eyes wide as coins, a look down at her hands, a look at Regulus, astonishment all over her.
"I felt it! Was that the cool one, the..."
She cut herself off and shut her eyes again, terrified the feeling would slip away, and when they opened her face was pure I can do this too.
First time she'd touched magic, and the excitement wouldn't stay down anywhere in her body.
Her eyes came open again, fixed on Regulus, shining. Hard to say whether the moss or the eyes burned brighter.
He looked over and gave a small nod.
Lina's grin stretched wider and she turned her head to survey everyone still blind, though her arm stayed rock steady.
Cuthbert glanced at her, then at Regulus, sidled quietly over to Alex and elbowed him. "You get it yet?"
Alex had kept his eyes closed and said nothing, brows shifting slightly. Ten-odd seconds more and he opened them, looked down at his own fingers, then up at Lina.
She was still riding high, and catching him looking, she beamed at him, wide and open, the cold white light on her face lending it a brightness.
Alex withdrew his gaze, let out a soft breath, ignored Cuthbert entirely, and turned to Regulus with a nod.
Samuel opened his eyes last. A quick glance toward Alex, withdrawn just as quickly, and a quiet, "Got it."
Regulus gave him a second look.
Lina's excitement was real. Samuel's slowness was theater.
He'd found it long before, held his tongue, and waited. Waited until Alex breathed out and opened his eyes, then filled the last slot himself so Alex wouldn't be at the bottom.
A small piece of calculation.
Alex handled Lina and Samuel. Holding the moderate pure-bloods and the half-bloods together was the position he occupied in this little group.
Samuel understood that, and had long since worked out how the machinery ran.
So he didn't get ahead of Alex. He put himself last on purpose, propping Alex up a rung on the way, and Lina with him.
No grabbing, no jostling. Quiet and steady.
Regulus said nothing, only looked at Alex.
Ordinary talent, that one, dead last of the five. But having someone willing to think on his behalf counted for something.
It proved nothing much, though.
Half a minute's spread on something this small was worth nothing, and finding the door was a world away from walking through it.
Anyone who followed him would turn out fine, provided they listened and worked. Alex had never fallen short there.
"Everyone got it?" Regulus withdrew the mental connection, his voice back to normal. "Hold on to that feeling."
"Now use your own magic to touch what's around you. Moonlight moss in the stone cracks, Luminescent fern under the tree roots, and a few luminous Mushrooms under that old oak."
"No eyes. Find it with magic." He raised a hand and pointed out a few stretches at random. "There, there, and there. Spread out, don't bunch up. I'll be watching."
They scattered.
Cuthbert bolted off first, wand shoved into an inner pocket, moving like Flossie let off the lead.
He crouched at a slope of broken rock, shut his eyes, frowned, groped along the ground for a while, came up with nothing, shifted position and closed his eyes again.
Lina headed straight for the nearest crevice, glancing back at Alex after a couple of steps.
Samuel picked a direction further out without a word and walked toward it slowly.
Alex gave Lina a nod and made for the rotted timber.
Hermes dawdled. Not one of the spots Regulus had pointed out got a visit; he drifted sideways in the other direction instead, watching from the corner of his eye.
Caught looking, he turned smoothly, put his back to them, and pretended to search.
Regulus let it go.
The moss was a simple matter once you said it plainly.
Those specks of cold white sat scattered among glowing plants of every color, and anyone patient enough to look closely could pick them out by eye. It only cost time.
Magic sense saved the labor. One pass and you knew which clump was genuine, no need to squint over every patch.
How this lot went about it, whether they treated it as a contest, cut corners, or actually settled in and worked, he didn't intend to police.
Each of them came at it differently.
Cuthbert had it down as a game. Alex would take it seriously. Lina wanted to look good in front of him. Samuel had too much going on behind the eyes and might well gather less on purpose to avoid standing out.
As for Hermes, Regulus threw another glance that way.
Still dawdling, and every dawdling step took him nearer the deep forest. His eyes kept flicking inward. The idea of slipping in hadn't left him.