Three actors in Western films who are past their best, go to small Mexican town, thinking they are giving a promotional performance. However the town is being terrorised by a gang of outlaws and they are mistaken for their on screen persomas.
The idea of actors being mistaken for their on screen characters has been done better (eg Galaxy Quest) but Steve martin and Chevy Chase have enough comic ability to carry this film.
3/5 
Steve Martin
Chevy Chase
Martin Short