CowboyJamesFranciscusseeksfameandfortunebycapturingaTyrannosaurusRexlivingintheForbiddenValleyandputtingitinaMexicancircus.Hisvictim,calledtheGwangi,turnsouttohaveanaversiontobeingshowninpublic.Anotherfilmfeaturingthestop-actionspecialeffectstalentsofRayHarryhausenaaa