Tell how it is ironic that bill and Sam become the victims by telling what was expected to happen and what did happen.Short and simple please

Bill and Sam have a brilliant plan to finance a crooked
deal they are planning in Illinois.  They plan to kidnap the son of a wealthy banker in
Summit, Alabama.  It seems quite straightforward.  They would kidnap the boy, ask for a
ransom of $2000, and then return the boy and take off.   They kidnap the boy and keep
him in a cave.  Bill is in charge of entertaining him while he is a captive.  The
problem is that the boy likes the cave and enjoys playing with the men.  He pretends
that he is an Indian chief named "Red Chief" and plans to burn Sam at the stake
and scalp Bill at daylight.  Bill gets nervous and they reduce the ransom to $1500. 
Then the boy hits Bill in the head with a rock from a slingshot, sending him sprawling
 across the campfire, and puts a hot potato down his back.  When they do get a note from
the banker, it does not contain the money they wanted.  Instead it contains a
counterproposal.  He will take the boy off their hands if they pay him $250 and get out
of town quickly. They agree, but they have to convince the boy to go home.  The ironic
part is that they were suppose to get the money for the kidnapping.  It was going to be
easy.  Instead, they ended up paying the man to get his son
back.