The two wizards chose not to stay the night on the island.

After returning from the market, Snape inspected the ship while Lucas waterproofed the purchased materials and packed them one by one into his personal storage bag.

Snape watched Lucas bustle around the whole time. The ship had already left its berth by then, sailing out once more into the open sea beneath a clear night sky thin with stars.

"We continue the Patronus Charm lesson tomorrow morning." Snape paused before heading to his cabin. "I expect you to show some improvement."

Lucas's hands stilled for a moment. Then he nodded.

The moment Snape's door clicked shut, Lucas drew his wand and gave it another tentative swing. "Expecto Patronum!"

Nothing. The wand produced nothing at all.

Lucas let out a sigh. Crash training didn't produce miracles.

He'd hoped Snape might share something from his own experience of casting the spell. Now it seemed like success would have to wait for the right moment.

The night passed without incident.

The following morning, Snape was waiting again, Boggart in tow.

"Before you attempt the incantation, I want you to think again — is there anything that makes you feel truly happy?"

Contrary to Lucas's expectations, Snape didn't launch straight into the drill.

He was discussing the sticking points with Lucas in an almost unhurried, even-tempered way.

Under that calm attention, Lucas found himself at a loss. The words wouldn't come.

He felt a faint urgency, a wish that he could say something, anything, in that moment.

Some feelings were hard to put into words.

Then Lucas thought of the Heartstrings bond.

He silently tried to pluck it, loosening his grip on his own emotions, sending through that vague, elusive, half-formed sense of happiness.

Snape's gaze snapped to him.

He had felt it. The Heartstrings, stirring.

He said nothing at first either. Then: "You don't have to tell me. Just recall in your mind whatever it is that makes you feel happy."

A series of uncertain, flickering moments of happiness kept coming through the bond.

Snape formed a hypothesis. He changed his approach.

"Think about what it is you want to protect." His voice was even. On the other end of the bond, Lucas felt Snape's awareness quietly withdraw.

That was to be expected.

Lucas patiently shifted what he was holding in his mind.

He started with not wanting Lord Voldemort to control Snape's fate. Moved through the powerful incantation with a magical intensity of eight. Through the moment he had destroyed Lord Voldemort's soul fragment.

Gradually, he came to feel that he truly could protect Snape, that he would not hand Snape's fate to anyone else.

He really was Snape's favorite student.

Snape felt the newly formed thread grow steadily warmer. The fingers resting on the arm of the sofa curled slightly, as though reaching for something.

His breathing quickened for a moment.

He could feel fierce protective intent coming through the bond, but threaded with self-doubt, which made it too unsteady.

The memory itself was strong enough. It was only that the emotions were too layered, too conflicted. That alone was keeping the spell from activating.

Snape understood Lucas perfectly. He was a cautious wizard. Even when he wanted to protect someone, as long as he hadn't actually done it yet, he would doubt himself.

Snape's own Patronus had come from the day he had been willing to give himself up. He had believed he would fall before the one he loved. He had believed he would no longer sleepwalk down the wrong path.

That was the day his Patronus appeared.

He did not want Lucas to learn this spell by traveling a similar road.

He had felt the boy's sincere emotions, and with it came a guilty twinge, the feeling of having glimpsed something that belonged to someone else's heart.

Who was it that Lucas wanted to protect?

Snape gave a dry cough. "That's enough."

He found himself meeting Lucas's eyes.

"Professor, are you feeling warm?" Lucas asked, with what sounded like genuine concern.

"Focus on your emotions." Snape steered back to the problem. "This spell requires an unwavering will to protect. Your understanding of it has a flaw."

Lucas looked at him, puzzled.

"The key is whether you want to — not whether you are capable of doing it."

Snape laid out the core of it: "A large number of wizards draw on a happy memory as the power behind the spell. Happiness is a definite thing. Certain."

"Other wizards choose the conviction of protection. You have to believe that you possess enough will to protect — not that you will definitely succeed in protecting someone." Snape took a sip of water. He almost never drank during a lesson.

But teaching a student was like looking into a mirror.

Had Lucas not proposed learning this spell, had he not struggled so long to cast it, Snape would never have thought about the Patronus Charm from this angle.

He even felt an impulse to try it himself, right then and there.

He was quite certain the form that emerged would still be a doe. But the process would be different.

"I need to... believe that my will to protect won't change?" Lucas had grasped it.

He turned the problem over in his mind, and for a moment his thoughts scattered in a dozen directions at once.

Snape assumed he hadn't fully landed it yet and added: "For you, all you need to do is believe. The vast majority of wizards get stuck on mispronouncing the incantation, or incorrect wand movement, or a head full of distractions, and yet plenty of those wizards still manage to produce a Patronus."

"Don't overthink this, Lucas." Snape's tone was final. "That is your problem."

He felt the Heartstrings tremble faintly on the other end.

Lucas hesitated, then drew his wand. He traced the movement with practiced ease and spoke the incantation.

"Expecto Patronum."

A successful casting needed no dramatic intonation. No shouting.

Not even a Boggart to serve as a trigger.

From the tip of Lucas's wand, a mass of white mist surged out, curling and drifting through the air in wispy tendrils.

The tendrils coiled for a long time. The magic was more than sufficient, but no solid animal shape condensed from the mist. Not yet.

"You can stop." Snape rose from the sofa. He stuffed the black balloon back in place; the Boggart had no role to play today.

"For you, the process of practicing this spell is the process of clarifying your own thinking. You don't need a Dementor to provoke you. Not right now."

A clever person could become their own obstacle, but now that the source of the problem had been found, Lucas should be able to cast the spell before they disembarked.

Snape told Lucas to try a few more times on his own.

Then he turned back toward his cabin, intent on writing a letter demanding the truth about this ritual from Dumbledore.

He was almost out of Lucas's line of sight when the young wizard called after him.

"Professor. You're a very good teacher."

Through the Heartstrings came genuine gratitude and joy.

Snape flinched.

"The person I want to protect is you." Lucas sent those warm, sunlit feelings pushing along the bond toward Snape. "You truly matter a great deal to me."

The small flicker of mischief behind it, wanting to watch Snape's reaction, was barely worth mentioning.

Snape was seared directly by the warmth flooding through from the other end of the bond.

He gripped the doorframe. Stood there frozen for a moment. Nearly walked into the door to his cabin. Then he turned without giving Lucas so much as a glance and pulled the door shut behind him.

But Lucas still felt it, transmitted back through Snape's end of the bond, unguarded for just one instant.

Shock. And self-loathing.

Lucas's smile froze.

➤ Next: Black Filaments

Chapter 275 - Black Filaments

The feeling lasted only a moment, but Lucas hadn't been wrong.

Bang bang bang — He knocked on Snape's cabin door.

Silence from inside.

Bang bang bang — He tried again.

Snape came to the door, visibly impatient.

"Professor, I just felt unwell!" Lucas stepped one foot into the room and pushed his worry across the Heartstrings toward Snape.

Just as he'd expected, nothing came back from Snape's end.

Snape had already found a way to seal off the Heartstrings.

Lucas stared at him and said it plainly: "Did I just feel your emotions?"

Snape said nothing. He stood in the doorway in silence, blocking Lucas from going any further.

"Did something go wrong with our ritual?" Lucas pressed.

It was all Dumbledore's fault!

Snape listened to Lucas's reasoning with a blank expression. Lucas had gotten nearly everything right.

But Lucas wasn't finished. "Did you feel my emotions too? Do you think I'm... revolting?"

A wave of disappointment and longing pushed through the Heartstrings.

Snape had never been in a more awkward situation in his life.

"Regarding the ritual, I suggest you ask the Headmaster once we leave the ship." He chose his words with care. "As for your insecurity, that is something you will have to deal with yourself."

Lucas looked thoroughly puzzled.

"There is nothing wrong with your body." Snape offered his diagnosis, and without going into any further detail about the emotional side of things, he gave Lucas a light push and shut the door.

---

After Snape discovered it, Lucas stopped closing off the Heartstrings.

He pushed small bursts of emotion across to Snape from time to time.

His progress with the Patronus Charm was going well. Every attempt was faster than the last, the white mist surging forth a little more readily each time.

On the fifth day of sailing, his Patronus gathered itself into a faint animal silhouette.

The ship passed through a layer of transparent magical shielding. No turbulence from a misaligned rift this time.

They entered Muggle waters without incident.

Both of them let out a breath.

Lucas went down to the lowest part of the hold to check the water tank. He had inspected it on the first day out at sea. The runic patterns in that section were tightly contained — under normal conditions, a check every few months was more than enough.

He had no particular reason to go down. Just an inexplicable restlessness that wouldn't leave him alone.

He climbed down to the tank lid engraved with runic patterns and noticed something near the edge: a small clump of black hair.

Lucas lifted the lid with a spell.

It was nothing but a floating mass of black algae.

Algae blooms happened. The fact that the tank's enchantments hadn't cleared it away came down to the quantity being too small to register, and the algae being entirely harmless. On top of that, their drinking water had been prepared on shore before departure. The water in the tank was only for washing up.

Lucas found some purifying potions in the storage room and poured them in.

A moment later, the potion dissolved and the water ran clear.

He didn't give it another thought.

That night, the first storm of the voyage found them.

The temperature dropped sharply. Distant thunder rolled at the edge of the sky, and according to their route, they were sailing directly beneath those clouds.

The ship was said to carry the highest-grade storm enchantments available.

But a few lines of text were not the same as reassurance when the full weight of nature was bearing down on you.

The closer they drew to the heart of it, the harder their hearts beat.

The sea, which had been steady for days, was heaving now, dark and violent.

The waves they had long since stopped noticing now sounded like something else entirely, something wrong.

Then the ship's defensive enchantments engaged.

A transparent barrier materialized from nowhere, catching the first massive wave that crashed against them. The spray scattered against the shield.

The second wave hit immediately after.

The seawater and the clouds overhead had both turned the same deep, striking black. Waves climbed higher and higher, and at their peak they curled above the very top of the mast.

The only comfort was that the barrier was still holding.

The entire ship sat wrapped inside a circular transparent dome. At least there was no danger of capsizing.

Then the wind climbed higher still.

A shrieking note ran through it. Gusts shoved them directly under the storm's core.

A black whirlpool formed on the surface below. The ship was being pushed off course, its magical propulsion grinding against the current in a losing contest of attrition.

This time, things were not going smoothly.

Their ship began to spin.

Snape and Lucas couldn't keep their footing. They stumbled, slammed into each other, broke apart, and each grabbed the nearest railing to hold on.

"Get to the cabin!" Snape shouted over the wind.

He cast something on Lucas, unclear what, but Lucas's shoes suddenly went heavy, which kept him upright as the deck lurched beneath him.

At the heart of a storm like this, spatial travel was impossible. They were trapped.

Lucas understood the situation. He stopped arguing and turned straight back for the cabin. He had a storage bag in there, and a few tools inside it that might be worth something.

He felt his way into the tumbling cabin.

Below was chaos. Decorative objects had fallen everywhere. The glass table had shattered, and Lucas crunched across the shards to grab his small supply bag from where he'd stowed it.

He pulled out a shrunken rubber dinghy, a flying carpet, and a broomstick.

Against waves that size, the odds of any of these tools doing much were not good.

Better to wait until they cleared the storm's center, then use them.

Lucas turned to Snape's potions case and drank down the Ageing Potion. Reverting to an adult form when danger hit had become something close to habit by now. He then took out a Water-Breathing Draught. The potion would save him the magical energy of casting the Bubble-Head Charm.

A moment later, Snape, still up on deck laying enchantments, saw an adult Lucas come back up.

This young wizard still hadn't understood that the point of sending him to the cabin was that he was a minor. His size had nothing to do with it.

But Lucas had already started up the mast.

He climbed fast and steady, a sharp contrast to the slow, careful pace during repairs. He reached the top, the edge of the protective barrier just above his head.

The magical mast powering the ship's operation had been concealed under ornamental plating. Without it, the cracks were visible.

The barrier above them was going to fail. It was a matter of when, not if.

And when it did, the sea conditions would likely be at their absolute worst.

Then something worse happened.

Even over that roaring, deafening chaos, both wizards heard it at the same time: a metallic explosion from somewhere inside the cabin.

There was nowhere safe left on the ship.

Snape cursed under his breath and charged inside.

The water tank had burst. A layer of water covered the sitting room floor, and floating through it were black, hair-like strands.

The strands had no offensive quality. They weren't even a magical creature, just unsettling in color, nothing more.

Snape wedged himself against the door frame to stay upright.

Before the lights shorted out, he confirmed it. Not a magical construct. A magical omen.

He had read about this once, in something he'd taken as a fairy tale at the time.

The author had noted specifically that across the long centuries of wizards venturing out to sea, encountering this algae was exceedingly rare. Not every storm came with a warning like this. Too few people who had lived through it survived to pass the story on. Strictly speaking, there was no definitive link between the black filaments and a shipwreck.

The author had treated it as nautical lore. A reminder for seafaring wizards to err on the side of caution. If such an anomaly appeared, change course at the first opportunity.

Because the second half of the legend held that once a vessel entered the heart of a storm, those seemingly harmless black filaments would begin to multiply, rapidly, relentlessly, breaking down everything on a magical level.

And in the end, they would drag whatever unprotected wizards remained down into the dark.

➤ Next: Arms Around Each Other's Shoulders