Episode two starts with another flashback, this time to right before the outbreak, in Indonesia. We see a scientist who recognizes that the Cordyceps fungus has evolved to infect humans, and suggests the military just bombard Jakarta and burn it to the ground because there is no containing the infection once it’s begun. It’s a cool little scene that helps set this show apart from other zombie apocalypse stories by showing the efforts to prevent the infection from spreading, and the immediate effects before the apocalypse begins.
The rest of the episode follows Joel and Tess escorting Ellie through a ravaged Boston, looking for the Fireflies. Along the way, they see hordes of infected just grouped together, mostly not moving, almost like they’re hibernating, since there are no humans to feed on.
What’s new is that Tess explains to Ellie that the infected share some sort of connection, a hive mind. There are vine-like tendrils running across the entire city that connect the infected with the fungi that created them. What’s more, the hivemind transmits information through said tendrils, so if you step on one, infected on the other side of town can “hear” you and chase after you.
Like the cordyceps infection itself, this is based in real biology; the roots of fungi are called mycelium, and they link up beneath the ground to form a vast network that’s also connected to plants and trees. In fact, the mycelial network has more connections than there are pathways in the human brain, and can stretch for thousands of miles. German forest ranger Peter Wohlleben uses the phrase “Wood Wide Web” to describe the mycelial network, which trees can use to send warnings about approaching danger via electrical signals, or even nurse their sick neighbors back to health by passing along nutrients.