Wallace's Ping Pong O'Matic Automated Home Leisure System has hiccuped badly during field trials. Then, when the pigeons next door ruin Gromit's washing, man and dog face a hefty bill. So when they see an invitation to attend an Invention Convention -- with a big cash prize for the best invention -- they have no choice but to enter. So begins Anoraknophobia, which brings the pair face-to-eyepatch with the sinister Herr Doktor Count Baron Napoleon von Strudel, inventor of the Acme Utility Anorak, and his scary, spider-taming wife, Queenie. The so-called von Strudels seem strangely familiar to Wallace, however. And our heroes soon find themselves entangled in Operation S.P.A.R.R.O.W, a diabolically evil plan to brainwash the cream of British brainpower -- with serious implications for the future of table tennis and other indoor sports.