Lupin was confused. He could tell that Ivan had given him the Wolfsbane Potion, but it was not the full moon. How was he supposed to turn into a wolf?
Before he could ask, however, a light mist appeared over the lake and Sirius and Ivan disappeared in front of him.
…
At the same time, the boat was silent as it sailed steadily across the lake. It was as if it were being pulled by an invisible rope. There was no need for any paddling as the boat moved slowly towards the centre of the lake.
No one dared to speak along the way, as they were all worried that they would disturb the Inferi in the lake. The surroundings were frighteningly dark, and only a faint green light could be seen flickering in the distance.
Sirius stood on the ship with his wand aloft, lighting the way.
Ivan, on the other hand, was very interested in the boat. He sat on the bow and slowly stroked the boat. It was wet and slippery to the touch.
Even at his current level of alchemy, he could not see how the ship worked. Perhaps Voldemort did not create the ship through alchemy, but enchanted it with some powerful magic.
As Ivan studied it, the boat suddenly slowed to a crawl.
'We're here!' Sirius whispered.
Ivan looked straight ahead, and through the mist he saw a smooth rocky island in the middle of the lake.
It was about the size of a classroom, and it was completely empty except for a one-meter-tall pedestal on which sat a stone basin from which the green fluorescence came.
Ivan swayed as the boat beneath him slowed to a stop.
Sirius took the lead and stepped onto the island, heading towards the central stone basin. After a moment's thought, Ivan followed suit.
'Is that what Regulus drank?' Sirius murmured, looking towards the stone basin and into its glowing emerald green liquid.
Just by looking at it, one could tell that it was poisonous. Drinking it would definitely not feel good!
"Yes… Master Regulus ordered Kreacher to supervise him as he drank the potion…" The elderly house-elf sobbed as he recalled the events of the past.
Sirius was silent for a moment, his gaze fixed on another locket in the basin. "If Regulus took out the Horcrux, why did he make the same thing and put it back?"
"Probably trying to confuse Lord Voldemort into believing that his Horcruxes still exist, so that he won't be able to create more and die in battle," Ivan said, analyzing the note Regulus had left in the fake locket.
Unfortunately, Regulus's plan fell through, and Kreacher was unable to destroy Voldemort's Horcrux, as the fake Horcruxes placed there would have entrapped Dumbledore if he had not appeared.
Ivan shook his head at the thought. Regulus had risked his life to set this up, only to have his allies killed by mistake. The old professor had it bad, having to suffer so much to get his hands on a Sybet…
Sirius gave the basin a long look, but did not touch it. He turned to the house-elf, who was still sobbing.
"Kreacher, show me where Regulus was dragged from the lake."
Kreacher nodded vigorously and led Sirius to the left side of the island.
Ivan did not hurry to follow. He hesitated for a moment, then gently waved his wand, and a faint fluorescent glow appeared on the floor of the basin. The glow connected with each other and formed a single line of words, which quickly fell silent.
There, he cast a triggering spell that would alert anyone who approached the text.
In case Dumbledore tracked them down after they left.
Of course, it could also be seen by Lord Voldemort, which would be interesting.
Ivan smiled and left without hesitation.
Sirius was crouched on the floor, his face grim, his left wrist sliced open and blood dripping from it in a grotesque pattern.
Ivan stood in silence, watching, unsurprised.
Sirius had previously mentioned to him that blood brothers were related by blood, and that he could use a spell to temporarily reinforce this link to locate Regulus.
However, this was apparently a form of Dark Magic, and it was unknown which book Sirius had read about it, but it seemed to be quite restrictive, otherwise Sirius would not have had to come to this island to perform the ritual.
It took Sirius about two minutes to complete the drawing, and he placed his right hand on top of it, murmuring an unintelligible incantation.
The blood on the ground reacted immediately, as if it were alive, climbing up the palm of his hand and gathering on the back of Sirius's hand to form the same pattern.
'Oh good, he's still here!' Sirius exclaimed, his body trembling with excitement.
The fact that the spell worked proved that Regulus's body was still there, perfectly preserved and not torn to pieces by the Inferi and melted into the lake.
Unable to contain his excitement, Sirius cast a Bubble-Head Charm on himself, gripped his wand, and plunged into the Black Lake.