Fort Invincible was released in the year 1951。Fort Invincible is also called as Only the Valiant, Sólo el valiente, Præriens musketerer, Obesegrade fortet, Lannistumaton linnake, Avamposto degli uomini perduti。
Capt. Richard Lance (Gregory Peck) is unjustly held responsible, by his men & girlfriend, for an Indian massacre death of beloved Lt. Holloway. Holloway (Gig Young) is killed while escorting a dangerous Indian chief to another fort's prison. The chief escapes. Knowing their fort is in danger of Indian attack, Lance takes a small group of army misfits to an abandoned nearby army fort to defend a mountain pass against the oncoming Indian assault. Their mission is to stall for time until reinforcements from another fort arrive. The men in this small group of malcontents, deserters, psychopaths & cowards all hate Capt. Lance & wish him dead. Much to their chagrin, the men recognize that Lance's survival instincts, military knowledge & leadership are the only chance the group has of staying alive.