Four months after Vaughn's murder by the traitorous Gordon Dean and his associate Ivan Curtis, a grief-stricken Sydney teams up with Renée Rienne, a French freelance assassin and fugitive on the CIA's most wanted list who knew Vaughn from their past association with Prophet Five, to ask for leads in order to track down the killers before they can strike again. Meanwhile, Jack enlists a reluctant new agent, Thomas Grace, as Vaughn's replacement at APO, and Weiss struggles to decide whether or not to accept a promotion that would force him to move to Washington D.C. and leave his colleagues at APO. During this time, Sydney, Dixon and Weiss travel to Amsterdam to track down Curtis who is in the process of buying a potential weapon.