Tokyo 24-ku

Enter the 24th Ward, a man-made island inside Tokyo Bay. Three of its inhabitants: Shuuta, Ran, and Kouki, have been best friends since childhood, but after a deadly incident, everything changed. A year later, reunited for the first time, they receive a mysterious phone call. On the other line is a familiar voice—from a friend who’s supposed to be dead. Together, they’ll have to save their home.
(Source: Funimation)
Note: The first episode was a 1-hour special.