A laughable premise--executed, however, with considerable panache. Retired Major General Huckleby, now president of Howson Chemicals in New Jersey and worth about $900 million, is an angry patriot. And when his wife is slain in a N.Y. bank during an attack by terrorists of the Puerto Rican liberation movement, Huckleby decides to give the nation an object lesson. He hires a brilliant mercenary and arranges for him to import terrorists from Ireland, Germany, and Syria to form a combat team to take over Manhattan. Not quite as dumb as it seems, the plan includes parking trucks filled with explosives from Howson Chemicals at the entrances to all the tunnels and bridges of the island and blowing up one or two just to show purposefulness. Then a billion dollars is to be transferred to a fully fueled jet at Kennedy and the terrorists will abscond to their respective countries and finance their homegrown liberation schemes. But the terrorists who accordingly arrive in the States are none-too-stable, and a few trip themselves up before the plan gets put into motion. Still, Manhattan's first black mayor finds himself hard-pressed when terrorists at Con Ed blow out all power lines to the Bronx; the cops dispatched to the Bronx leave Manhattan unguarded; that the Harlem River bridges are blown, the cops can't get back, and the island is taken over. Finally, the fumbling but successful terrorists are blown up in midair by the top mercenary, who then successfully escapes with the suicided general's daughter. . . or does he? Somehow there is a step-by-step plausibility to much of this nonsense--a cut above the similar terrorist fantasy-fandangos that have been proliferating lately.