The reader is left to assume that Arthur "Boo" Radley mended Jem's pants. The children had been sneaking around his yard and house, trying to sneak a peak at Boo, and when they run away, Jem's pants get stuck in the Radley fence. While Nathan Radley responds with a shot gun, it seems Boo responds by watching the kids from a window and seeing what has happened.
In an act of compassion for Jem, Boo goes out to the fence, untangles the pants, and sews them up. When Jem finds them, they are folded and mended - though not neatly, as a practiced seamstress might have sewn them. He keeps this fact to himself for a while, apparently mulling it over and trying to make sense of it, before finally sharing the information with Scout.
Slowly, Jem is realizing that Boo is not the monster he has been made out to be. He has proven himself to be kind and gentle now on several occasions; besides mending Jem's pants, he has left the children various gifts in the tree, including hand-carved soap figures, and he put the blanket around Scout during the fire. Ultimately, Boo proves himself heroic in his care and concern for the children when he saves their lives after they are attacked by Bob Ewell.
In an apparent act of kindness, Boo Radley has mended Jem's pants, which caught on the fencing on the Radley's property.
Because of the Dill's curiosity and penchant for the dramatic, he dares to go onto the Radleys' porch and peep through a loose shutter into the window of their house. Once in the Radleys' yard, Jem and Scout make a saddle of their hands and arms and lift Dill up so he can hold onto the window sill and peer inside. Dill sees little more than a dim light, so the children go around to the back of the house. Jem then sneaks onto the back porch and peers into a window. Suddenly, Scout sees the shadow of a man with a hat that moves toward Jem, but it passes back and goes around the house.
Jem leaps in fear from the porch, holds the gate for Dill and Scout, and then the children run through a collard greens patch. When they hear the blast of a shotgun, the terrified children head toward the fence by the schoolyard that is made of strands of barbed wire. Jem holds the bottom wire up for Scout and Dem to slip through, but when he tries to slip under this wire on his own, his pants become caught in one of the barbs. Unable to free his pants from the clutches of the wire, Jem frantically climbs out of them and runs, leaving his pants behind.
Of course, the neighborhood responds to the shotgun blast. After stepping out of their houses, they stand around trying to determine what happened. Atticus soon notices that Jem is not wearing pants. Quickly, the imaginative Dill fabricates an explanation; however, Dill's story that they were playing strip-poker is a dangerous one. Miss Rachel scolds Dill,
Do-o-o Jee-sus, Dill Harris! Gamblin' by my fishpool? I'll strip-poker you, sir!
Jem amends Dill's declaration, saying that they were only playing with matches, not cards. Still, he has not resolved the problem of the whereabouts of his pants, so Jem sneaks back to the Radleys' late in the night. He finds his pants folded neatly on the fence, mended with erratic and crude stitches, and he retrieves them.
One afternoon, Jem reveals to Scout that his pants were sewn in a crooked manner and folded on the fence as though someone knew he would return.
This is a disturbing thought for Jem. Shortly after this incident, the children discover some twine left in the knot hole of a large tree, so Jem wonders about Boo Radley's apparent surveillance of him and his sister.