Touring After the Apocalypse, Vol. 2

Youko and Airi's next stop is Umihotaru, a rest stop in the middle of Tokyo Bay famous for its nighttime view. But with the Aqua-line tunnel from Kawasaki flooded, they're forced to take a huge detour all the way to Chiba. On the way, they make a stop in Akihabara to investigate a mysterious radio signal. Could someone still be alive there.?