One Piece: The Cursed Holy Sword

The Straw Hat Pirates take a brake on Asuka Island, home to the Seven Stars Sword. Which is known to be the most valuable sword in the world. But always holds a curse within it. After Luffy and Chopper had their meal, they all went back to the Going Merry. Where Zoro was on watch and Usopp doing some repairs. Only they discover from Usopp that Zoro went off without a word. A fleet of Marines spotted the Going Merry and chased them off the port. Our heroes managed to get them off their tail, and docked at a lake where they came across a village. Which is home to the sacred Seven Stars Sword. And villagers have a job in sealing away the curse of the sword. But the village was attack by an army of Marines lead by a trio of swordsmen. Among the three is Zoro, who became a member of this group. The Straw Hat Pirates were confused on why Zoro would abandon them. Zoro has his own reasons for doing this. And it has to do with the leader of the Marines, Saga. A childhood friend of his from his trainee years. Who is cursed with the sword and plots to release it's power on the night of the Red Moon. Will Luffy and the others be able to prevent the spreading of darkness from this curse? And what was the relationship between Saga and Zoro?