What is a brief summary about chapters 3 and 4 in al capone does my shirts?

In the book Al Capone Does My Shirts by Gennifer Choldenko, Moose and his family have moved to Alcatraz Island.  In chapter three the two children, Moose and his sister, are being taken on a tour of the island by Theresa a seven year old friend.

Theresa takes the kids past the guard tower and around the area.  She tells them about the different notes that she has taken on the various criminals.  She explains that they are not supposed to meet any of the criminals.  She also wants to take them to the morgue.

The names of some of the prisoners are realistic people from history; Al Capone and Machine Gun Kelly.  She also introduces the kids to words for things like murder such as "Rub Out."

Theresa takes them to the morgue where Moose meets another girl.  The girls name is Piper an after she observes Moose's Sister Natalie she asks him if the girl is stupid. Natalie has some problems and lives in a mental world very different from the other's.  Moose is protective and at times embarrassed by his sister.

At the end of the chapter his mother finds him and his sister and is upset.  She had not seen their note and was worried about them.

In Chapter four, Moose wakes to his father's presence reading the newspaper.  He has missed his busy father.  Moose talks about how difficult it is to talk to his sister and to never get a response like she is made of stone.  Moose also talks about the changes in his voice from highs to lows.

Natalie is preparing to be sent to the school called Esther P. Marinoff where she will reside.  His Mother doesn’t think Moose should accompany Natalie and them on the trip.  However, his father makes sure that he goes. Natalie and Moose have a different relationship formed by the dynamics of Natalie's abilities and inabilities.  She likes to bring books to Moose and they read and play games using the pictures.

Natalie's trip to the coastline is uneventful.  Using a book and the pages and making comments back and forth, Moose helps to guide Natalie off of the boat. Moose begins to feel sick about his sister having to live at the school.  He tries to tell himself it is the right thing and the best thing for her, but he does not feel that way inside.  He feels sick.