DM must save his reputation and the world when Squawkencluck's artificially intelligent defence super computer goes despotically insane!

Danger Mouse is responsible for ruining yet another of Professor Squawkencluck's inventions and putting the security of HQ in jeopardy. The Professor finally loses her temper and installs a fully automated Headquarters Electronic Assault Defender which is quite big. Big H.E.A.D. for short. DM instantly antagonises the machine and finds himself and a onesie-wearing Penfold locked out of HQ and under attack from a range of inanimate objects.

Things escalate when Big Head takes Squawkencluck, Colonel K (and his hologram version) prisoner. DM and Squawkencluck must bury the hatchet, and not in each other's heads, to overcome Big Head together. Her genius and DM's innate ability to destroy any gadget through inappropriate use will save the day.