Success

Snape's private storeroom was in his office, and if Albert barged in, he would most likely alert Snape. Normally, Hogwarts professors' bedrooms were in a cubicle next to their offices, so even if Snape was asleep, barging in would still be unwise.

Albert's original plan was to lure Snape away by having the Weasley Twins create a disturbance, allowing him to then break into Snape's office and steal the medicine. However, after taking Felix Felicis, Albert's first thought was to steal a pot of Mandrakes from Greenhouse 3.

Why did he want to steal a pot of Mandrakes from Greenhouse 3? Albert himself didn't really know, but that was the intuition brought by Felix Felicis that told him so, so he decided to go to Greenhouse Three first.

As night fell, the gates of Hogwarts Castle were already closed, but this did not stop Albert, who left the castle through a secret passage on the Third Floor.

The heavy rain outside had stopped, and the air was damp and cold.

Albert tightened his cloak and, before stepping out of the secret passage, used Transfiguration to conjure boot covers to cover his boots and prevent them from leaving evidence on the muddy ground.

The Boat Dock was some distance from the greenhouse, Albert quickened his pace toward it; everything went smoothly. He reached the greenhouse entrance and easily unlocked the door to Greenhouse 3, which was sealed by Anti-Alohomora Charm, using a wire. Before entering the greenhouse, Albert waved his wand, conjuring an orb of light to dispel the darkness within.

The plants cultivated in Greenhouse Three were all dangerous, so Albert dared not be careless at all. He carefully avoided the dangerous plants in Greenhouse Three and walked to the flower pot stand in the corner.

Albert was very familiar with these things; well, what could he do? He had just repotted the Mandrakes that morning. He waved his wand again, casting a spell on the flowerpot so that it floated up and followed behind him.

Before leaving, Albert also took the brown earmuffs from the box next to him.

As for why we need to wear ear covers?

Albert thought that Sickle come in handy.

Returning the way he came, Albert went into the secret passage, removed the boot covers from his boots, and used Vanishing Spell to completely destroy the evidence.

Just before exiting the narrow secret passage, Albert glanced at the time on his pocket watch; there was still some time before the agreed-upon time.

"I'll leave this in the Room of Requirement for now, and return it a couple of days after the mission is complete." As Albert thought this, a crazy idea suddenly popped into his head.

Yes, it's crazy.

Albert also clearly felt that he should heed this impulse.

However, he still decided to put this crazy idea into action.

So Albert started walking toward Snape's office, the Mandrakes floating behind him the whole way.

Snape's office was underground. Albert had never been there, but it wasn't difficult to find Snape's office using the Marauder's Map.

A few minutes later, Albert was standing in front of Snape's office.

The entrance was indeed enchanted with Anti-Alohomora Charm, but this still couldn't stop Albert's wire. Perhaps due to Felix Felicis, it didn't even take him a few seconds to unlock the door with the wire.

The door creaked open as Albert pushed it open, and he carefully stepped inside, his gaze falling on the door to the private storeroom. Instead of rushing to find the Potions ingredients he needed, Albert gently closed the door, took out earmuffs from his cloak pocket, and put them on. Only then did he cautiously make his way to Snape's bedroom.

Then... Albert did something astonishing: he actually pulled the Mandrakes out of the pot, and the next moment, a terrible cry filled the entire room.

Snape, who was fast asleep, was suddenly awakened by the crying of the Mandrakes, and then, without warning, was knocked unconscious by the crying.

As Albert stuffed the Mandrakes back into the pot, he looked at the completely unconscious Snape and muttered to himself, "That was exciting. When Snape wakes up tomorrow, he'll probably think he had a nightmare."

He took out his wand and waved it lightly, causing the fallen soil to fly back and cover the Mandrakes again.

Before leaving the room, Albert went to Snape's bedside and thoughtfully tucked the sheets back in before leaving the room and going to the private storeroom, where he used a wire to unlock the door.

Sure enough, the alarm went off.

Snape cast Protective Magic on his private storeroom, which would trigger an alarm if anyone broke in without dispelling the spell, and Snape would be notified immediately.

Unfortunately, the alarm went off but it was no use, because Snape had already passed out and might not wake up until tomorrow morning, so he would have no way of knowing what had just happened.

Albert used the Summoning Charm to easily find Snape's Graphorn egg, fragments of African Tree Snake skin, and Bicorn Horn. As for the Dragon claw powder, Albert didn't take it; it could be bought at apothecaries, though it was expensive, but that didn't matter, he had Galleon.

It won't be long before Snape discovers that someone is stealing the medicine, so Albert is also planning to mislead Snape into thinking that he is preparing to make the Polyjuice Potion.

Before leaving, Albert glanced at the Marauder's Marauder's Map. The Mandrakes's crying had indeed caused a commotion, but he still had plenty of time. From knocking Snape to opening the private storeroom and taking the three herbs, it had only taken less than a minute, and the others hadn't even had time to react.

After placing the materials in the conjured box, Albert left Snape's office. Before leaving, he locked both the private storeroom door and the office door again.

To paraphrase that saying: Quietly I leave, just as quietly I came; I wave my sleeves, taking with me the Graphorn egg, fragments of African Tree Snake skin, and the Bicorn Horn.

It truly lives up to its name as the Felix Felicis; the Lucky Potion is indeed worthy of its name.

Albert walked through the underground passage, glancing at the Marauder's Map every now and then. Filch had woken up and was coming over to figure out where the sound was coming from.

It seems that the two doors do provide some sound insulation.

The two passed each other almost without noticing, and Filch had no chance of noticing Albert under the Disillusionment Charm.

Before anyone else could react, Albert had already reached the Seventh Floor, placed the herbs and the Mandrakes in the Room of Requirement, and then returned to the Gryffindor Common Room.

The Fat Lady wasn't there, but that was good news for Albert.

Soon after, the agreed time arrived, and Fred opened the entrance to the Common Room on time, letting Albert in.

As for the castle behind him, which had fallen into complete chaos, that was none of Albert's concern.