Sydney soon discovers that the Passenger is Nadia Santos, her half-sister by the way of an affair between Irina and Sloane. After a rescue mission, Sydney's sister is taken by Sloane so he can get the formula that was stored in her brain by Rambaldi (actually her unique nervous system can replay the graphical hand movements encoded in the Rambaldi Fluid-protein strands that cause unconscious, movements like handwriting). Sydney rescues her again, but Nadia later elects to accompany Sloane in search of the Rambaldi artifact known as The Sphere of Life.