Mattheo might not be a genius who connects ingredients with powerful potions, nor does he produce a perfect incantation upon hearing a spell's name—he was, however, a dangerous boy, and because of that, Mattheo had the quickest mind of them all. For that very reason, it didn't matter if the party was taking place in the safety of the Hogwarts common rooms; his eyes followed Diana like a hawk every time she walked five steps away from him, sometimes following her with his hands in his pockets, but with the sharpest gaze directed at anyone whose eyes lingered a second too long on his girl.
Parties were meant to be fun—relaxing, even—but Mattheo only thought of stories about boys who drugged girls at parties and so on. Mattheo knew that in the wizarding world, these stories could become twice as terrifying: potions like Amortentia were sold in Joke Shops, marking incidents Mattheo didn't even want to consider happening to his friends or his girlfriend.
However, to the idiot's bad luck, Mattheo saw when his fingers got too close to Diana's glass, the one Mattheo usually held for her when she went to the dance floor with Daphne or followed Pansy to the crowded bathrooms. Suspicious, but distracted when Crabbe approached his side with a sarcastic comment followed by Draco's feigned boredom, Mattheo wasn't quick enough to warn his girlfriend when she returned to take a sip, encouraged by Goyle, who smiled mischievously.
Disliking the sight of Diana so close to his less reliable friends, Mattheo rested his arm on her shoulders, gently—but firmly—taking the plastic cup from her hand: "No, princess, take mine. If you want to drink, drink from my glass," Mattheo corrected, discreetly sniffing his half-empty cup without taking his eyes off Goyle, who slowly looked away with a pathetic act of indifference.
From the perspective of those who weren't there to see the tragedy unfold in three acts, it all happened quite randomly, with little reason, out of nowhere. Amortentia or any Muggle drug smuggled into the dungeons acted fast, before Mattheo could try to dispel it with liquids or take Diana to the safety of his dormitory.
Goyle could have fled, had Mattheo not been holding Diana with one arm and twisting the boy's neck with his free hand, unwilling to let him escape, although leaving Diana unattended wasn't an option either. Regulus didn't ask when he pushed his way through the crowd—a rough shove hit Goyle's left shoulder, holding him for Mattheo without knowing exactly why his best friend was so agitated. Lorenzo dragged Crabbe away, dubbing the pair Tweedle-dee and Tweedle-dum who share a single brain cell, while Blaise shot a questioning look at Draco, who seemed just as confused but hesitated to come to his friends' defense.
"Pans," Mattheo called, holding Diana by her back and waist, guiding his girlfriend into the care of Daphne and the other girl. "Take care of her for me, alright? Don't lose sight of her—lock yourselves in my room or something, but don't let her walk around."
Assuming that more than house points would slip through Mattheo's threatening fingers, Pansy opened her mouth to ask about the look shared between the three boys, but Lorenzo simply shook his head at her. With a nod, Mattheo took one last look to ensure Diana was in good hands before dragging Goyle out of the common room entrance while Regulus and Lorenzo followed, ensuring that help took an extra minute to arrive.
If a hanging green tie appears in the depths of the Quad Courtyard fountain along with a pair of shoes, Regulus wouldn't know how they got there. Lorenzo would be twice as ignorant when they find Goyle, his face unrecognizable from Mattheo's fists, hanging from the third-floor gargoyle after the Riddle gave him time to meditate on his misdeeds.
