Occlumency

At Grimmauld Place, Kreacher reappears oddly content while Sirius grows despondent as the holidays end. Snape arrives with Dumbledore’s order that Harry learn Occlumency in secret. Sirius and Snape nearly duel before the Weasleys arrive with Arthur, cured. That night, Harry tells Ron and Hermione about the lessons; Lupin later urges Harry to work hard.

The next morning, Tonks and Lupin escort the group by Knight Bus to Hogwarts. Before leaving, Sirius gives Harry a secret means to contact him. On the bus, Tonks keeps Harry’s identity quiet. Back at school, Harry fends off DA inquiries by citing “Remedial Potions.” Cho awkwardly invites a Hogsmeade date for Valentine’s Day; Harry accepts.

That evening in Snape’s office, Harry sees a Pensieve as Snape explains Occlumency and Voldemort’s Legilimency. Snape reveals Harry’s scar connection allows accidental sharing of Voldemort’s thoughts and that Voldemort may now exploit it. Snape removes his own memories to the Pensieve, then attacks Harry’s mind, forcing vivid memories to surface. Harry struggles to clear his mind, repeatedly collapses, and is berated for emotional weakness.

During a probe, Harry relives the Ministry corridor he ran with Mr. Weasley and realizes his recurring dream depicts the passage to the Department of Mysteries. Pressing Snape, Harry infers Voldemort wants something there; Snape denies details and orders continued practice.

Unwell and scar-aching, Harry reports his deduction to Ron and Hermione, who link it to Sturgis Podmore’s attempted break-in. Later, overcome by piercing pain and manic laughter in the dormitory, Harry senses Voldemort’s ecstatic triumph over some success. Ron helps him to bed as Harry fears Occlumency has left his mind more exposed.