Countdown

Mark continues his interrogation of Hellinger in a desperate attempt to find out when the next blackout will occur; Demetri must choose between helping Janis and Simon break into NLAP to stop the blackout from occurring, or turning the fugitive Simon in to the FBI; Lloyd finds the common denominator that can help him solve the complex equation he was working on in his flashforward; while Tracy fights for her life, Aaron discovers why Jericho was after her; and Nicole wrestles over her strong feelings for Bryce and what would happen if she told him she knew the whereabouts of Keiko.