In Harper Lee's To Kill a Mockingbird, how do the children claim to have spent the evening, when Mr. Radley fires his gun in his yard?

In Harper Lee's To Kill a
Mockingbird, the three kids—Jem, Scout and Dill—get together one last time
before Dill has to leave to go home to his mother.

The
children ask if they can go to Miss Rachel's fishing pool to spend some time. It is,
ostensibly, where they kids go (as far as the adults are concerned), but the three sneak
over to the Radley property; Jem and Dill have hatched a plan to look into the window of
Boo's house so they might catch a glimpse of him.

Mr.
Radley discovers that there is someone trespassing on his property, and after the kids
see a shadow on the porch, they take off while they also hear a shotgun blast. (The
reader finds out later that Mr. Radley aimed into the air, but the kids do not know
this.) As they are running "for their lives" (or so they think), Jem's pants get caught
on the fence and he has to leave them behind.

When the
three youngsters return, innocently, they find the adults all gathered outside to
investigate the disturbance. In explaining that Jem lost his pants while playing strip
poker with Dill, they say that they were playing at the fishing pool, where they had
said they were going in the first place. No one suspects that they were the ones
responsible for the commotion at the Radley place.