The day begins slowly as Weaver calls to say she'll be late, and Chen thinks she's developing a fever. Then multiple MVAs come in, quickly followed by two children suffering what appears to be smallpox. The staff panics, but not as bad as the patients, when a lockdown is ordered for the ER. The feverish Chen is quarantined with homeless Stan. Lewis takes charge as Weaver arrives and the police won't let her in. The girl infected by smallpox dies and Pratt embarasses Carter in front of her parents. Carter notices Pratt is sick as well, and sends him to Chen's room. Jerry phones the news, and the patients riot, nearly using a gurney to break open the emergency bay doors. Control of the ER is relieved from Weaver by an infection specialist. The staff prepares to stay, still not having a confirmation on whether it is smallpox or not, and the lockdown continuing as a result. Carter and Abby kiss after being quarantined together.