 In the beginning of the film, John McClane and Lucy have an argument  that eventually leads to them discussing her use of her mothers  last name, Gennero. This was also a discussion in the first  _Die Hard (1988)_ (qv) film, as seen when John McClane is searching  for the location of his wife, Holly, in the Nakatomi building. He  does not find her under Holly McClane, but does find her under her  maiden name Gennero.