Marco appears in The Bones on the Blue Line. While riding the subway with Dr. Lance Sweets, Marco got the news that he was finally leukemia free which excited him as he had been fighting the disease for most of his young life. He told Sweets he planned to travel the world and sleep with exotic women now that he was cancer free. However, an earthquake struck and both men were shocked by the appearance of a skeleton outside their window. The wave of water from the earthquake knocks Marco off his feet and he smashes his head against a metal pole, killing him instantly. His death devastates Sweets as Marco finally had his whole life ahead of him and he lost it in an instant.