Dumbledore asks Harry to wait in his office while they go search the grounds.
Harry sits stroking Fawkes, the phoenix.
Harry sees a large basin with odd carvings around the edges.
There's "silvery stuff" (30.20) inside, which Harry pokes with his wand.
The silvery stuff inside the basin draws Harry into another place: a courtroom.
He looks around at the crowd and at Albus Dumbledore, who is seated in the room.
But no one in the room can see Harry.
Harry watches a group of Dementors lead in a prisoner: a young Igor Karkaroff.
Mr. Crouch is acting as judge.
Karkaroff offers: "I wish to be of use to the Ministry. I wish to help. I – I know that the Ministry is trying to – to round up the last of the Dark Lord's supporters. I am eager to assist in any way I can ..." (30.43).
Karkaroff starts listing names of Death Eaters he has known, but none of them seem that important to the Ministry.
Finally, he accuses Severus Snape.
Crouch answers, "Snape has been cleared by this council [...] He has been vouched for by Albus Dumbledore" (30.80).
The memory ends with Professor Dumbledore promising, "[Snape] is now no more a Death Eater than I am" (30.84).
Karkaroff is dragged back to Azkaban.
The next trial is of Ludo Bagman.
Ludo's defense is, "well – I know I've been a bit of an idiot –" (30.90).
Everyone in the courtroom (except Moody and Mr. Crouch) seems charmed by his friendly, self-deprecating manner.
One of the members of the jury stands up to say: "We'd just like to congratulate Mr. Bagman on his splendid performance for England in the Quidditch match against Turkey last Saturday" (30.101).
So, obviously, this jury isn't exactly unbiased.
Ludo Bagman is released, and Mr. Crouch is furious.
The next trial is of four people, one of them "a boy in his late teens, who looked nothing short of petrified" (30.107).
They're accused of using the Cruciatus Curse to torture Frank and Alice Longbottom.