One year after Kaito's death, Zack decides to travel to New York and leaves Team Baron's leadership to Peko. However upon arriving in New York, he is confronted by Peko's older sister, who tells him that Peko is in deep trouble. Apparently Shura, a former member of Team Baron that Kaito previously exiled, has become a thug, forming a gang called Neo Baron. Zack returned to Zawame City to set things right. Before going to save Peko with Oren and Jonouchi, Zack is given a new Sengoku Driver, packed with a Kurumi Lockseed and a new Marron Energy Lockseed by Mitsuzane after the latter saves him from Neo Baron's Kurokage Troopers. Despite gaining an Energy Lockseed, Zack is unable to use it due to no Genesis Drivers being around. Zack fights against Shura, but is overpowered as the fight becomes three to one. Peko gives Zack the Genesis Core from Kaito's destroyed Genesis Driver allowing Zack to assume Jimber Marron Arms and defeats Shura before collapsing in Peko and Azami's arms.
Zack's fate is unknown and in the credits of the Gaiden, he is shown talking to Kaito, asking him why he was spared during their final encounter with each other, dancing with him in the night before Kaito disappears, leaving Zack dancing alone.