Herman discovers he's the new lord of Munster Hall in England. The family sails to Britain, where they receive a tepid welcome from Lady Effigy and Freddie Munster, who throws tantrums because he wasn't named Lord Munster. An on-board romance had blossomed between Marilyn and Roger, but on land Marilyn discovers Roger's family holds a longstanding grudge against the Munsters.
On July 2, a giant alien mothership enters orbit around Earth and deploys several dozen saucer-shaped 'destroyer' spacecraft that quickly lay waste to major cities around the planet. On July 3, the United States conducts a coordinated counterattack that fails. On July 4, a plan is devised to gain access to the interior of the alien mothership in space, in order to plant a nuclear missile.
An LAPD officer begins to terrorize his next-door neighbors after learning they are an interracial married couple.