A suicide bomber and his victims are set to become travelers, but the bomb explodes and only Donner, the bomber, survives. Devastated by his failure, Donner tries to betray the traveler program to the authorities, but the entire hearing is populated by travelers who hold a trial and convict Donner of treason. Donner is overwritten by a new traveler, who must serve Donner's prison sentence, and reports that things in the future are getting worse despite the changes enacted by Traveler teams in the 21st. Luca approaches Donner in prison, implying that he has lost faith in the Director. Ken, David's boss, believes David's relationship with Marcy is inappropriate. Upon meeting Marcy, he believes she has defrauded the system. Marcy saves David's job by repaying her benefits. Grace, Trevor's guidance counselor, and Jacqueline, Carly's social worker, genuinely care about them, respectively. Grace tries to help Trevor with his academics, and Jacqueline promises that she will not let the system fail Carly and her child. Philip discovers that gambling outcomes are deviating slightly from the historic record.
Philip, while under the influence of drugs, commits to memory an anti-viral formula sent via messenger. The information is passed on to fellow Traveler Derek via Jenny so it can be synthesized and distributed to other Traveler teams as well as people targeted to be saved in order to minimize the spread and mutation of a flu like virus that historically killed 70,000 people. However, two weeks after dissemination, people around the world start getting sick with a virus even more dangerous than the original one. With no contact from the Director, and the death toll rising, Marcy and the team rush to find a solution before it's too late.
Three months after the events with the Quantum Frame, Mac and Kat are working through their issues during her first trimester. Marcy has moved out of David's apartment and has taken a job as an X-ray technician at a local hospital. Philip has traded one addiction for another, but is in denial about it. Trevor is growing concerned with the lack of communication from the Director. The discovery of a murdered Traveler team puts Mac on the trail of Vincent.
Flight Detroit - Orlando (DTW - MCO) $61+ Flight Houston - Orlando (HOU - MCO) $73+ Flight Houston - Orlando (IAH - MCO) $73+ Flight Washington - Orlando (BWI - MCO) $79+ Flight Philadelphia - Orlando (PHL - MCO) $83+ Flight Chicago - Orlando (ORD - MCO) $87+ Flight Denver - Orlando (DEN - MCO) $89+ Flight Hartford - Orlando (BDL - MCO) $95+ Flight Washington - Orlando (DCA - MCO) $97+
Three high-ranking Travelers are sent back by the Director to put Grace on trial for violating protocols, overwriting a person who was not assigned to be her host, and sabotaging the Grand Plan. Mac and the team must give testimony at the trial that will determine if she should be overwritten or not. Meanwhile, the Faction is trying to replenish its numbers by overwriting people with the stored minds in the Quantum Frame. It transpires the trial was staged by the Director to flush out a Faction member from within the three Travelers judging Grace, which it successfully does, this leading to Mac's team securing the Quantum Frame.