Lone Riders by Daniel Pennac
Back in jail and sick of failure, the Dalton brothers turn on Joe and bet that whoever first earns a million dollars will lead the gang, then break out and go their separate ways.
Books
Daniel Pennac is a French novelist. Together with Tonino Benacquista he wrote two Lucky Luke albums, Lucky Luke versus the Pinkertons and Lone Riders.
Back in jail and sick of failure, the Dalton brothers turn on Joe and bet that whoever first earns a million dollars will lead the gang, then break out and go their separate ways.
Set under President Lincoln, Lucky Luke crosses swords with Allan Pinkerton, the ambitious detective who fancies himself the marshal's successor.