Contains spoilers for this episode.
The armed strangers are Henry and Sam, brothers hiding from Kathleen’s forces. Henry explains that he once gave FEDRA information about Kathleen’s brother in exchange for medicine Sam needed. With Kathleen’s militia hunting them, Joel agrees to help the brothers escape Kansas City through underground passages. The tunnels are empty, and the group finds children’s drawings in a shelter beneath the city. They reach the outskirts, where Kathleen and her fighters confront them in a suburban cul-de-sac. The ground splits open and an infected mass pours out. Joel covers Ellie from a nearby building as the group tries to get clear; a huge infected kills Perry, and a child clicker attacks Kathleen.
After the escape, Joel, Ellie, Henry and Sam rest at a motel. Ellie and Sam talk privately about fear and what infection means. Sam reveals that he was bitten. Ellie shows him her healed bite and presses her blood against his wound, hoping it will help. In the morning, Sam has turned. Ellie tries to reach him, but Henry shoots his brother to stop him from attacking her. Grief overwhelms Henry, who turns the gun on himself. Joel and Ellie bury the brothers before continuing west. Ellie writes “I’m sorry” on Sam’s slate and leaves it on his grave.