(Monocle secure? Here comes the third-person narrator.)
Ever since all the business with Bucket and Jo, Mr. Snagsby hasn't been himself.
Shmoop's going to go ahead and guess that this might be because he's a reasonably decent human being and seeing how Jo lives in the horrible hell-hole that is Tom-all-Alone's has unbalanced him somewhat.
Everything is freaking him out – every time a customer comes in and asks for him, every time a bell rings. Dude's having some major flashbacks.
Mrs. Snagsby, meanwhile, is trying to do some detective work to figure out what in the world is wrong with him.
All her thoughts center on Jo and figuring out just how he is connected to her husband.
Oh, and here's a shocker – Jo never showed up the next day for more of Chadband's preaching. (Yeah, we're totally floored too.) But somehow Chadband ran into him in the street and threatened to take him to the police if he didn't come.
So the next evening at Snagsby's house, everyone is ready to listen to Chadband's gibbering nonsense, er , instructive speeches. When Jo walks in he is all confused. He quickly looks at Mr. Snagsby (since he's the only person there who's ever been the least bit nice to him).
Mrs. Snagsby sees this look and thinks that...her husband is Jo's father!
She's no detective Bucket.
Chadband lays into Jo, talking about how Jo really needs to understand the universal light and truth (meaning Christianity). He talks so well that Jo totally falls asleep.
The narrator pipes in here to say that there might be a good story that Jo needs to hear (i.e. the story of Jesus), but no one cares enough to tell it to him the way it should be told to a totally illiterate boy.
Meanwhile Mrs. Snagsby works herself into hysterics.
She needs to be taken upstairs, so the meeting breaks up. Jo tries to leave.
Guster has been quietly moved by Jo's rag clothes and generally depressing state. She finds him quickly before he leaves and gives him some food, along with a sympathetic word about also being an orphan. Aww, Guster. She's a nice one.
Snagsby slips Jo a little bit of money before he leaves... which Mrs. Snagsby sees.