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.
Unfortunately the movie Captain Thunder is not yet available on HBO Max.
| Directing | Antonio Hernández | Director |
| Writing | Pau Vergara | Screenplay |
| Writing | Ambrós | Comic Book |
| Production | Antonio Mansilla | Producer |
| Writing | Víctor Mora | Comic Book |
| Production | Pau Vergara | Producer |
| Camera | Javier Salmones | Director of Photography |
| Sound | Luis Ivars | Music |
| Art | Alejandro Fernández | Art Direction |
| Editing | Iván Aledo | Editor |
