As children, The Gunners could not have imagined that by the time they were sixteen years old, one of them would turn her back on the others, and the group would be so fractured by the loss, the sudden and unexplained absence of this one, that within weeks the other friendships would also dissolve, leaving each of them in a dark and confounding solitude. Mikey Callahan became a sinkhole; everything inside sort of loosened and then just collapsed.