The story of "Captain Thunder and the Holy Grail" is set during the Third Crusade in Palestine, when Captain Thunder finds in the dungeons of a fortress a dying Christian named Juan de Ribera, who entrusts him the mission to restore to Spain a cup which is the Holy Grail, stolen from an ancient order. Thunder, with his inseparable friends Crispin and Goliath, and a Viking princess named Sigfrid, will face an evil feudal lord and his black "devils", who are terrorizing the population of low Aragón.
as Capitán Trueno
as Sigrid
as Crispín
as Goliath
as Sir Black
as Rey Ricardo Corazón de León
as Venus
as Juan de Ribera
as Txerrán
as Jador
as Al Kathara
as Ariadna
as Saturno
as Adelbert
as Morgano
as Hassan
as Martín
as Soldado de Al-Katara