1: For this debate, cordyceps brain infection (CBI) is a fungal infection that effectively turns humans into zombies upon the infliction of a wound, inhalation of iinfected spores, or death. CBI has caused the collapse of humanity, with only areas under strong military control and survivalist groups (such as the Fireflies) having been able to live functionally.
Joel is a lone survivor, but he encounters a Firefly who tasks him to escort a teenage girl named Ellie to the other side of the US in exchange for weapons and supplies. Ellie is immune to CBI, and there is strong conviction from the Firefles that a cure can be developed by running scientific experiments on her. While escorting her, Joel develops a strong bond with Ellie, who reminds him of his own daughter who he lost to CBI years earlier. Upon arrival at their destination hospital, it is revealed to Joel (and not Ellie) that although a cure can be developed, Ellie would die in the process.
Joel instead chooses to save Ellie by violently rampaging through the hospital, extracting Ellie while she is unconscious, and driving away to a remote location. Ellie is unaware of what had happened, and to avoid survivor's guilt, Joel lies and says they were unable to find a cure.