Public opinion turns against Wickham in about two seconds, and most of the action in this chapter happens through letters.
Mr. Gardiner writes to say he has tried to find out from Wickham's direct superior if he has any relatives or friends who might hide him in London; on second thought, though, Elizabeth might be in a better position than anybody to give that information, i.e. she knows Darcy.
They receive a letter from Mr. Collins, who says that Lydia's actions will forever ruin the chance that the other daughters will marry.
He congratulates himself on not marrying Elizabeth after all and suggests that they cut Lydia out of their life forever.
Nice guy, right? That's some real Christian compassion.
Mr. Gardiner writes again to say that things might be worse than feared—Mr. Wickham has gambling debts. Big ones. He's still looking, but Mr. Bennet is on his way home.
When he does get home, he says he's finally learned his lesson—which, great, but isn't it a little late for that?