What situation is the main character confronted with at the beginning of the novel The Hitchiker's Guide to the Galaxy?

As The Hitchhiker's Guide to the Galaxy opens, main
character Arthur Dent is faced with a rather significant challenge - bulldozers
preparing to tear down his house in order to construct a highway bypass. He does his
best to fight this demolition, refusing to vacate the premises and arguing that adequate
notice was not given. Unfortunately for Dent, there is no turning back with the plans
for demolishing his house, as this is not just any highway construction project. Aliens
are preparing to move to the next stage of their invasion of Earth. Some, including
Arthur's friend Ford Prefect, have been on Earth for years becoming familiar with the
planet and its possibilities, and now they are proceeding with the next step in their
plan.