Gringotts

Hufflepuff's Cup, the last of the Hogwarts Founders' relics, had likewise been made into a Horcrux by Voldemort.

Silvan had always known where it was and had planned to find a suitable opportunity to tell Dumbledore or Harry.

He just hadn't expected Dumbledore to know as well.

"Professor, how did you find it?" Silvan asked curiously as they left the wand shop.

"Guessing would be a more accurate word," Dumbledore said. "You must remember what we learned from Hokey—oh, sorry, I forgot you hadn't seen that memory."

Dumbledore paused before continuing. "She was Hepzibah Smith's House-elf. That witch had once possessed both Hufflepuff's Cup and Slytherin's Locket, and had shown them to the young Tom Riddle."

"I bet she died horribly," Silvan said softly.

"You know, the young Tom Riddle was very skilled at beguiling people. He always had a way of making others lower their guard without realizing it," Dumbledore said, but he did not deny Silvan's words.

Not long after Hepzibah Smith had shown those two treasures to Tom Riddle, she was murdered, and both the locket and the cup vanished without a trace.

"After learning that Slytherin's Locket had been turned into a Horcrux by Tom, I knew the cup must have become one of his Horcruxes as well, but I could never find any clues."

"Until recently—come to think of it, I'm sure you remember how Lucius Malfoy was living in constant terror every day because he had lost one of Tom's possessions."

"Of course." With a casual wave of his hand, Silvan made the diary float out of his pocket and hover quietly by his shoulder.

"I really have to thank Lucius Malfoy. This gift he sent has saved my life more than once."

Even a wizard as composed as Dumbledore could not help laughing