The children plan to touch Boo Radley’s house to make him come out, and when that doesn’t work they plan to pass him a note with a fishing pole.
Dill is the one that first thinks up the idea of making Boo Radley come out. The children are “fairly sure” Boo Radley is still in the house. No one has ever seen him. Boo fascinates Dill, because the Finch children have told him stories about Boo stabbing his father in the leg with scissors. Jem’s description of Boo is also very imaginative.
Boo was about six-and-a-half feet tall, judging from his tracks; he dined on raw squirrels and any cats he could catch, that's why his hands were bloodstained. (ch 1)
The children seem to believe that Boo Radley got a bad rap, even though they are afraid of him. Dill dares Jem, and Jem has never turned down a dare. He says making Boo Radley come out is “sort of like making a turtle come out” so they develop a plan.
"He'll probably come out after you when he sees you in the yard, then Scout'n' me'll jump on him and hold him down till we can tell him we ain't gonna hurt him." (ch 1)
Jem runs and touches the house, but no one comes out. So the children come up with another plan. They are going to pass a note to Boo Radley with a fishing pole.
Jem was merely going to put the note on the end of a fishing pole and stick it through the shutters. If anyone came along, Dill would ring the bell. (ch 2)
Atticus catches them trying to deliver the note, and tells them to stop “tormenting” Boo. They try to explain. The children are not trying to be mean. They want to help Boo, in their way. They feel sorry for him. Dill thinks that if “he'd come out and sit a spell with us he might feel better” (ch 2). After all, he’s been “shut up for a hundred years with nothin' but cats to eat” and that would be rough on anybody!
The Boo Radley stories may seem like harmless fun, but Boo Radley is one of the "mockingbirds" of the story. He is an innocent victim of prejudice. His life has been nightmarish, even if it doesn’t quite live up to what the children imagine. Boo really is a prisoner in his own house. The children's concern for him shows compassion.