"Expelliarmus!" Severus says sharply, disarming Sirius as he quickly enters. "Oh, vengeance is sweet. I hoped I'd be the one to catch you." The Potions Master says. "Severus-" Remus tries. "I told Dumbledore you were helping an old friend into the castle. And now, here's the proof." Severus cuts the werewolf off. "Brilliant, Snape. Once again you put your keen and penetrating mind to the task and as usual, come to the wrong conclusion. Now if you'll excuse us, Remus and I have some unfinished business to attend to!" Sirius snaps.

Severus again levels his wand at Sirius' throat, his black eyes full of hate and anger at the sight and sound of his childhood bullies.

"Give me a reason. I beg you." Severus bites. "Severus, don't be a fool-" Remus says. "He can't help it, it's habit by now-" Sirius growls back. "Sirius, be quiet!" "Be quiet yourself, Remus!"

"Well, look at you two, quarreling like an old married couple!" Severus says, bitterly. "Why don't you run along and play with your chemistry set?" Sirius says mockingly, despite the wand at his throat.

Severus presses his wand closer to Sirius. "I could do it, you know. But why deny the Dementors? They're so longing to see you...Do I detect a flicker of fear? Oh, yes..." Severus says in cruel enjoyment. "A Dementor's Kiss...one can only imagine what that must be like to endure. It's said to be nearly unbearable to witness...but I'll do my best." The black-haired man says venomously. "Severus, please-" Remus tries once more.

Severus ignores him. "After you." He says to Harry and the other two...but next thing he knows, Harry has hit him with an 'Expelliarmus', and launched him at an old, dusty bed. When he eventually wakes up to an empty room, Severus dashes outside, already getting a sinking feeling of what's to come, dashing outside to see a transformed Remus and Sirius. Severus stands protectively, and unarmed, in front of the students with his eyes wide as he's forced to remember a situation just like this in his youth...