On the Verge of Eruption

"Severus Snape!" Sirius was the first to notice Snape's arrival. He shot to his feet like an agitated dog, glaring viciously at Snape.

"I ought to have spoken with you alone, Potter." Snape's usual sneer curled across his lips as he saw Sirius sizing him up. "But Black—"

"I'm his Godfather," Sirius declared loudly. "And Dumbledore allowed me to stay at Hogwarts to visit Harry."

What Sirius feared most now was that this loathsome Snivellus would ruin what little time he had left with Harry.

"Well, what a coincidence, isn't it? I was sent here on Dumbledore's orders too." Snape spoke coldly, his voice growing increasingly venomous. "But do stay, Mr. Black. I know how much you enjoy... well, how shall I put it, feeling involved."

"What do you mean by that?" Sirius demanded.

"Oh, I merely mean that you must be rather—ah—frustrated, and bored as well, aren't you? Unable to do anything useful for the Order of the Phoenix." Snape deliberately stressed the word "useful."

Sirius's face reddened at once. With a victorious smile at the corner of his mouth, Snape turned to Harry.

"Originally, I had no wish to involve myself in this matter at all. I have no desire to give extra lessons to a wizard as utterly talentless as you, but unfortunately, Professor Slughorn has been very busy lately, and Dumbledore has little time himself. So this burden has fallen upon my shoulders." Snape said coldly. "The capable do more work, after all."

Snape put particular emphasis on "the capable do more work."

"W-what is it?" Harry suddenly had a bad feeling.

"The Headmaster asked me to inform you, Potter, that I will be teaching you Occlumency." Snape said. "Private lessons."

"What?" Harry asked blankly. "Learning what?"

Snape's sneer became even more pronounced.

"Occlumency, the art