From observing his family, Day can tell that Eden isn't doing too well. Poor guy seems really sick.
Day and Tess reminisce about when they first met—she was just a little girl in the Nima sector, and he felt sorry for her and shared some of his food with her.
She was hurt, so Day took her in and let her stay with him; when he told her to leave a couple days later, she wouldn't and so they've been scavenging together ever since.
They're hiding out when they hear a couple of police offers talking on the pier above them. The officers are talking about how the plague is popping up in the Zein district and it's a stronger strain.
They find a weird metal door that has symbols carved into the surface, including the Republic's flag and the number 318. Curious. Very curious.