The Beast of the Baskervilles

What?! How?!
No, no, no! My operation was flawless!
Rachel! That useless brat! You can't make anything good with trash!
I was flawless—Kgh!
Gwen kicked Henry aside, sending him rolling across the rooftop.
You're the trash, you scumbag bastard!
...Pfft.
What's so funny?
Do you truly think you've won, Gwen Lestrade?
As if! You still lose!
You worked oh-so hard to save dear Rachel...
But alas, it's too late!
Henry started maniacally laughing, taunting Gwen.
That thing is the pinnacle of Baskerville's magicology!
No detective can undo what I've done!
You'd need a god to help you to reverse my work!
I don't need a god or even some famous detective to do that.
...Because there are still people trying to save other people.
Gwen took out a blueish ampule and a syringe from her inner pocket.
W-what is that?
It's the cure that Director Stapleton made.
It can't stop Rachel's mutation...
But it can remove the parts that mutated from Rachel.
Nonsense! That's not possible! The Monster of the Baskervilles is the pinnacle of magicology!
Shut it! Then you can call this the invention of a true genius magical scholar who risked his life to save a little girl! A legacy that transcends the pinnacle of magicology!
Gwen approached the limp monster and injected the shot.
She stroked the beast's chin with her hand, wet from the rain.
Time to get up, Rachel.
Just then, something beneath the middle of the beast's three heads began to twitch.
It looked like a muscle spasm at first, but it soon turned into the sound of flesh tearing apart.
*Riiip* *Crack*
Fur fell off in clumps while black liquid gushed out, instantly turning into vapor as it came into contact with the rain.
Boss, are you okay?!
I'm fine!
The layer of skin under the beast's mane started crumbling from the inside.
A silhouette of someone's hand could be seen through the crack.
Gwen started pushing away the beast's flesh with her bare hands.
Seeing the hand, Lily approached to help Gwen tear apart the hide and flesh.
Just... a little bit more...!
Its hide was thick, and it seemed like the small figure buried inside was drowning.
The two girls were soaked in sweat and rain, but continued digging through the beast's carcass undeterred.
When Gwen and Lily started panting from exhaustion, a purple liquid dripped onto the hide of the monster.
You should really learn how to solve things with more than just physical labor, Miss Gwen.
After all, what's the point of hiring an advisor if you don't request her services?
This smell... Was that a magic extraction reagent?
Its primary use is for investigating the magic residue of crime scenes.
It works by vaporizing the magic with the highest concentration on the area of contact.
It can also break magical bonds that have stopped circulating.
The beast's hide split with a loud crackling sound.
I suppose I can provide just a bit more assistance.
Gwen and Lily nodded, and the three dug through the split hide and flesh under the rain.
At last, the small body of a child was pulled out.
It was limp, but definitely the body of a human being.
...Rachel.
Gwen hugged Rachel's body, covered in black liquid, and wiped the young girl's face.
Rachel's drenched body was small and delicate.
Is Rachel okay, Boss?
I think so. She's breathing, at least.
Lily let out a sigh of relief and dropped to the ground. Gwen stood up with Rachel in her arms.
That was when they heard a desperate scream coming from the other side of the rooftop.
That's a lie!!!
Henry shouted with a reddened face.
This can't be...! This isn't real!
No genius would be able to do this!
It doesn't make sense! That's my magnum opus! I devoted my whole life to it!
Magnum opus? No, it was merely a knockoff created by a third-rate scholar.
If anything, that cure is the true masterpiece.
Jack Stapleton was truly every bit the genius they said he was.
I failed...? Again...?
Deep down, you knew it all along.
The Professor leaned closer toward Henry.
You must've known, since your career in magicology was a string of failures.
Your life's work is child's play in the eyes of a real genius.
Bullshit! That cure! I must've been the one who came up with it!
Give it back! It's mine! It's my creation...!
As Henry stumbled frantically towards Gwen and Rachel, the Professor emerged in front of him, blocking his path.
Standing in front of the beast's corpse, she leaned over to whisper into Henry's ear.
Henry.
I do hope you understood my notes on how the tail functions?
W-what's that supposed to mean?
Fufu... As I suspected, you have no clue at all.
...?
*Slither*
The sound of something wet slithering across the wet floor could be hear coming from the beast's tail.
...Huh?
Boss, look...!
The snake on the tip of the beast's tail slowly emerged from its slumber.
You see, an interesting fact about the chimera's tail is that...
It continues to act independently even after the main body has ceased functioning.
I made sure to leave a note on the very first page of my Lab Notes. Alas, ignorance prevails again.
What?
Before Henry could speak any further, the snake's giant mouth enveloped him and swallowed him whole.
Mr. Henry?!
Eeek!!!
A pitiful man's hopeless screams echoed across the rainy rooftop before coming to an abrupt halt.
Gwen and Lily, frozen stiff, could only stare in shock.
Well, I suppose that solves the mystery of Charles Baskerville's death.
Professor! Are you okay?
I'm quite fine. How about the two of you? Miss Gwen, Miss Lily.
I-I'm all right.
The snake, having swallowed Henry's upper body, twitched momentarily before collapsing.
The thud of the snake falling on the rooftop was accompanied by the growing pool of blood flowing between the drops of rain falling from the sky.
The Professor silently stared at the blood flowing under her feet.

It was a completely different place, but it was raining back then too...
There was blood on the ground, dispersing under the rain...
And the whole world was so gray that it felt suffocating.
Nothing had color at all—

Yes. No color, save—
What are you thinking about, Professor?
Fufu. Oh, it's nothing.
I suppose this marks the end of this case for real, this time.