Marco was one member of a three-man mercenary group sent to track down Serenity to retrieve stolen goods. Marco's accomplice Jayne Cobb tracked the vessel and led him and the third gunman to Malcolm Reynolds and Zoë Alleyne. Outside the cargo doors of Serenity, they threatened Malcolm and Zoë and demanded to know where the goods were hidden. Though he was defenseless, Malcolm maintained control of the situation and made a play to convert Jayne to his side as soon as it was made known that Jayne was the tracker. Marco repeatedly tried to regain Jayne's attention as Malcolm sweet-talked him, but failed. Jayne became disillusioned with his current employers and suddenly shot Marco through the leg, incapacitating him, and switched sides.