Seattle is under siege by masses of living dead, and the military struggles to prevent the virus from spreading outside the city.

Kate is tired of sitting around. When she learns that a rescue mission is heading back into the chaos, she jumps at the chance to tag along and put her unique skill set and, more importantly, swords to use. Lester finds a new way to deal with the situation: ignore reality with drugs. When he manages to find himself threatened, he joins with an unlikely ally to take the fight to the dead.

Meanwhile, Mike makes use of his journalistic skills to find the source of the virus, in the process discovering a way to escape the city. Two mysterious words fuel his mad quest: Lazarus Black.