Jack Jack lived at the Mall alone before the others joined him. He sleeps in the electrical shop that his father owned. He is the Tribe scientist and often works with Dal. Lex calls him "specky geek", "nerd", and other similar names. He needed others to help him survive: that's why he allows Amber and her party into the Mall. But when Lex comes following behind, issuing threats and menaces, Jack lowers the Mall grille, first the inner, then the outer, thereby trapping Lex, and those with him, Ryan & Zandra. Until now he has remained hidden. Now he introduces himself to Amber, and shows everyone around. For some time Jack refuses to believe that all the adults in the world are really dead, and spends hours with his radio gear trying to make contact with anyone who might listen. Later on in Season 1 he invents a water filtration system with Dal, a wind-turbine to generate electricity, cctv surveillance, security alarms and so on.