Last time, we saw Pip and Herbert in mutual confidence
-- Pip confessed his love for Estella to Herbert, and Herbert confessed
his engagement to a young woman named Clara (whom he must wait to
marry until "looking about him" has yielded a dependable income).
Herbert and Pip went to see Mr. Wopsle at the theatre, where they
witnessed a travesty of Hamlet. And Pip received a letter
from Estella saying that she would be coming to town; Pip was to
conduct her from London to Richmond, where she was going to be introduced
into society. Pip, in his anxiety to see Estella, went to the coach
office several hours in advance of the time, and was persuaded by
Wemmick -- who passed by on his way to Newgate -- to join him in
his rounds. Pip was thus introduced to the inside of Newgate Prison
-- and was back in plenty of time to meet Estella's coach.