Creature from the Black Lake Part 4

Introduction

Hello everyone, welcome to our Walkthrough section for the Creature from the Black Lake Part 4 of Harry Potter Hogwarts Mystery! In the previous part, you uncovered the shocking truth behind Merula’s disappearance. What seemed like a terrifying encounter with the Black Lake creature turned out to be something entirely different — a potion gone horribly wrong. Penny’s investigation led to the discovery that Merula had been transformed by a botched Polyjuice Potion, leaving her barely recognizable. Your task is to bring her safely to the Hospital Wing for treatment.

Summary

Walkthrough

Video guides are available on our YouTube channel. Use the button below.

You’ll need to wait six hours before you can continue. Since this chapter is not time-limited, it is recommended to wait until this timer runs out.

Head to the Corridor once the waiting time is over. As you make your way to the Hospital Wing, you’ll find Filch and Mrs. Norris patrolling the corridors. Your task is to sneak past them and reach the Hospital Wing without getting caught.

To plan to pass Flich, you need to earn five stars within eight hours. The five stars are required to pass. Since this task requires a lot of energy, it is recommended to start it with a full energy bar.

Bonus progress actions are tied to your character. Prioritize these actions to save some energy. Slide the screen left and right to check all available actions.

Your plan is simple: since Filch is terrified of the Creature from the Black Lake, have Merula use that to your advantage. You tell Merula that when Filch draws near, she should leap out and give him a fright. If it goes to plan, Filch will bolt, and you can make a run for the Hospital Wing. Merula will agree, then she will spring out and successfully startle Filch.

Penny will point out that the scare might have been a bit rude and will ask how you feel about frightening Filch.

There are three different options to choose from. All of them will eventually lead to the same outcome, so feel free to take your pick.

Following that, you’ll decide to head to the Hospital Wing. Go to the Hospital Wing to continue the story. You’ll have slightly different dialogue lines depending on your year. In any case, Chiara will be waiting for you there, eager to help you restore Merula to her original state as soon as possible.

To examine the patient, you need to earn five stars within three hours. The five stars are required to pass. Since this task requires a lot of energy, it is recommended to start it with a full energy bar.

The bonus progress actions are tied to Chiara. Prioritize these actions to save some energy. 

Chiara will say that the best thing to do now is wait. Merula has a long road ahead of her, but she should make a full recovery. There are three options to choose from. If you like Merula, it is recommended to pick the first option. 

You’ll then decide to head to the Great Hall since it’s almost time for the Hallowe’en Feast. For now, you should at least inform the professors that Merula is safe.

Proceed to the Great Hall when you are ready. When you arrive, Professor Dumbledore will begin his announcement, welcoming everyone and happily declaring that the Creature from the Black Lake has been handled. Hogwarts is safe once again. All your friends will be relieved and overjoyed that the mystery has been solved — and that the Hallowe’en Feast has been saved.

To celebrate Halloween, you need to earn five stars within eight hours. The five stars are required to pass. Since this task requires a lot of energy, it is recommended to start it with a full energy bar.

The bonus progress actions are tied to your character. Prioritize these actions to save some energy. Slide the screen left and right to check all available actions. 

Ben will come over to you and wish you a Happy Hallowe’en. He’ll add that everyone is relieved to hear the creature isn’t a threat and thank you for spreading the word. He’ll then ask if you haven’t forgotten the promise you made him at the start of all this. 

There are two different options to choose from. These options will influence some dialogue that will follow, but they won’t impact the story.

In any case, Ben’s wish was to set up a campfire by the Black Lake. You’ll want to do this as well, since it will be the perfect opportunity for Merula to recover and finally tell you in detail everything that happened.

Go to the Lakeshore to continue the story. You’ll all gather around the campfire and begin to enjoy each other’s company. Soon, Merula will arrive, looking fully recovered, and you’ll ask her to explain everything that happened in detail, which she will agree to do.

To learn the truth, you need to earn five stars within eight hours. The five stars are required to pass. Since this task requires a lot of energy, it is recommended to start it with a full energy bar.

Bonus progress actions are tied to Tonks and Merula. Prioritize these actions to save some energy. Slide the screen left and right to check all available actions. 

Merula will explain that she tried to impersonate you using a Polyjuice Potion to get you into trouble, but it went terribly wrong. Tulip Karasu’s toad splashed into the potion, ruining it, and when she drank it, she became part toad. She then used the bottles you found by the Black Lake to contact Penny, hoping her potion skills could help. 

Merula will apologize for what she did and ask if you can just put it all behind you and forget it ever happened.

There are two options to choose from. If you like Merula, it is recommended to pick the first option. 

Following that, Ben will come over and hand you a gift. He’ll explain that it’s something to remember this adventure by. It’s small, but you should think of it as a meaningful memento.

However, as you’re talking, something unexpected happens — you catch sight of glowing eyes again in the distance. It’s strange and unsettling, reminding you that the mystery of the Black Lake is far from solved. The creature’s true nature remains unknown, and the lake still holds its secrets.

This will mark the end of the Creature from the Black Lake Adventure. Hit the Collect button to claim your reward. You will receive 4 Gems, 3 Chocolate Frogs, and 1000 Experience Points. You will also receive a Potion Bottle Tappie.

You’ll earn the achievement for completing the adventure.

As the embers of the campfire glow and the students settle around it, a sense of calm returns to Hogwarts — for now. Merula has been restored, Penny is safe, and laughter once again drifts through the halls. Yet, the Black Lake still holds its secrets, its dark waters hiding eyes that gleam with an otherworldly light. You’ve faced fear, uncovered the truth behind a botched potion, and saved friends from danger, but the lake whispers that not all mysteries are meant to be fully tamed. Hogwarts may sleep peacefully tonight, yet somewhere beneath the surface, magic stirs, and the adventure is far from over.

Thank you for reading.