D' Artagnan and Porthos received the order of Richelieu, which protrudes as a powerful figure of the French church, a plot against the King of France Louis XIII. uncover. Disguised as a monk enters D' Artagnan the Church, in which the conspirators act. D' Artagnan, however, exposee and can only escape with the help of Porthos . Meanwhile the Duke of Montresant tried to force his ward to overwrite all their possessions to him, so that he can support the Flemish troops. The Duchess refused and is sent with her maid to Brescon. D' Artagnan and Porthos decide to follow the women…
Unfortunately the movie The Secret Mark of D'Artagnan is not yet available on HBO Max.
| Directing | Siro Marcellini | Director |
| Writing | Siro Marcellini | Screenplay |
| Writing | Ottavio Poggi | Screenplay |
| Writing | Milton Krims | Screenplay |
| Camera | Alvaro Mancori | Director of Photography |
| Writing | Ottavio Poggi | Story |
| Production | Ottavio Poggi | Producer |
| Art | Amedeo Mellone | Art Direction |
| Sound | Carlo Rustichelli | Music |
