Lucky Luke 49 - The Dalton’s Amnesia

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.