A new military vehicle goes breaks out from a training exercise and heads in to the city.  Section 9 gives pursuit but there's not much they can do until they get the specs on the machine.  As Mokoto and Batou follow in the Tachikoma, the rest of the group work to find out what's happening.  As it turns out, one of the creators of the tank who had died earlier from a disease had his co-worker hook his brain into the machine.  It now appears that he's out to find his parents who wouldn't allow him to have a cybernetic body in order to live longer.