After packing up, Harry went to the atrium, intending to use the Floo Network to head home from work. But when he reached the Fountain of Magical Brethren, he spotted someone in the distance and immediately turned around on instinct.
"Hey, Harry!" Cormac McLaggen greeted him warmly.
"Why didn't I use an Invisibility Charm?" Harry muttered irritably, then turned back and smiled at McLaggen.
"Why are you leaving so late?" McLaggen asked politely.
"What about you? Working overtime?"
"You know I never work overtime. Only losers work overtime. Oh, right, we're having a party later. Want to come?"
"No, Ginny's waiting for me at home..."
"Oh, don't be so boring." McLaggen threw an arm around Harry's shoulders and steered him toward the companions waiting for him. "Don't worry, none of those stuffy old Ministry officials will be there. Remember Anne? She used to be in Potions Club. She didn't look like much when she was young, but now she's completely changed."
In 1996, after Slughorn replaced Severus Snape as the Potions professor, none of the older Hufflepuff students except Ernie Macmillan took Slughorn's advanced Potions class. Just as Harry Potter had organized Dumbledore's Army the previous school year to study Defense Against the Dark Arts in resistance to Umbridge, they had formed a Potions Club to complete Potions homework and essays. They did not use the Room of Requirement, though; instead, they borrowed one of Professor Sprout's greenhouses.
"I don't remember you being a member of Potions Club," Harry said, trying to recall.
McLaggen was not a member of the Slug Club either, though Harry had seen him at many club events.
"What does that matter? We're winners, Harry. Winners should enjoy the fruits of victory—parties, wine, music. What's the point of going home so early?"
"Don't you know?"
"Know