After Tokyo was destroyed by an earthquake and rebuilt by Genom, Voomers (VOodoo Organic Metal Extension Resource), advanced robots, became commonplace. Although Voomers take care of most of the manual labor in Genom City, they can malfunction and become Boomers. Boomers are crazed robots that are often involved in violent and criminal activities, running rampant and destroying everything in their path. Sometimes they work alone and other times they are under the orders or control of humans.
The A.D. Police was created to counter Boomer threats. They are Genom City's anti-robot crime division, specially trained to deal with Boomer-related situations. After the Knight Sabers were created, they would often work with the A.D. Police to stop Boomers.
A.D. Police seemed to have two different alerts for Boomers. One was Sequence N, which referred to the "Nano-Stampede" some Boomers went on. They would go about and fuse themselves to anything mechanical nearby, growing larger and stronger as time went on. They also became harder to kill, so had to be eliminated very quickly. This alert was heard only in A.D. Police: To Protect and Serve.
Sequence B referred to a normal Boomer attack. It involved the Voomer in question breaking down and becoming a Boomer, attacking anything in a seemingly random manner. Typically, Sequence B alerts involved a large blue combat Boomer and were heardonly in Bubblegum Crisis and Bubblegum Crash.