Arthur gets to London on Sunday. The narrator has a little aside to talk about how dumb it is that everything is closed on Sundays, the one day of the week that laborers have off. (Open brain, insert snack: this was actually a big political to-do at the time – it was illegal to have museums, theaters, and other entertainment places open on Sundays for religious reasons. Dickens was one of the people who thought this was ludicrous and lobbied hard against the so-called Sunday Laws.)
So anyway. Arthur sits at an inn thinking back on his miserable childhood. His mom was a crazy religious nutcase, and she and his dad were constantly fighting. Also, he went to some hardcore fundamentalist school.
He decides not to stay at the inn but to go home.
Home is a miserable falling-down wreck of a place. It's also where the Clennams' lending and financial services business is.
Flintwinch, the old, nasty servant, answers the door, totally not excited to see Arthur. (Dude, the man's been gone for 20 years, at least pretend to be somewhat happy to see him.)
Flintwinch tells Arthur that Mrs. Clennam is now an invalid who hasn't left her room in fifteen years. And she is still a horrible, horrible, horrible old woman. (Did we mention that she is horrible?)
Mrs. Clennam couldn't care less that Arthur is back. She seems weirdly proud of being kind of a quadriplegic. She asks if it's snowing outside, and Arthur is all, "Um, it's September." She says haughtily that she's forgotten all about the seasons. OK, wacko.
Arthur reminds his mom about the watch his dad sent her with his final words on the back.
She eats dinner, then reads a section from the Bible that is all about smiting enemies as violently as possible.
Affery, the elderly maid, takes Arthur to his room.
There, Affery tells Arthur how while he was gone Mrs. Clennam and Flintwinch decided he would marry her (Affery). Affery is totally terrified of both of them and repeats over and over how she clearly had no choice but to do whatever they told her. She does seem kind of hopeful that Arthur will stand up to them, since he owns half the business.
Arthur asks about the tiny girl he saw in his mom's room doing embroidery, and Affery tells him that that's Little Dorrit, who is "nothing; a whim" of Mrs. Clennam (1.3.103).
Flintwinch comes and tells Arthur that he knows he wants out of the firm, and that his mom is going to be totally mad about it. Honestly, though, we're not sure his mom is ever not mad, so, not a big deal there.
Just before he goes to sleep, Affery tells Arthur that his old girlfriend, who he left behind when he went to China, is now a rich widow and can be his for the asking.