Four soldiers of fortune are hired by a wealthy Texan oil baron to rescue his kidnapped wife (Cardinale), who's been spirited across the Mexican border by a band of mercenaries led by Jesus Raza (Palance). The four rugged professionals, each regarded as a specialist in his selected field - an expert marksman and tracker (Strode), the explosives master (Lancaster), horse handler (Ryan) and one skilled in tactics and weaponry (Marvin) - make their way across the treacherous landscape to retrieve the beautiful kidappee, but discover all is not what it seems...