Lucky Luke: The Dalton's amnesia (Lucky Luke #49)

After a fellow inmate, having received a blow to the head, forgets his own name and is freed as a brand new man, the Daltons start pretending to be amnesiac in order to escape the prison. So as to test their supposed amnesia – and hopefully allow them to retrieve their memories should it be real – they are put in familiar situations: bank hold-ups, train robberies... under Lucky Luke’s supervision, of course.