Bennett tracks Selig via highly secure files to a research base where Selig was studying aquatic regeneration. Ro and Zeta are also there on the trail of Zelig. Bennett takes his son James Jr. along and while Ro, a local boy and James go underwater in a sub, Agent Bennett spots and pursues Zeta. But the kids get in an accident. Zeta reveals himself and volunteers to go down and Agent Bennett goes with him. Zeta has to act as the rudder for the injured sub to get everyone to the surface in time. At the end Bennett has to choose his son over capturing Zeta.