Upon discovering a Unidentified flying object in American airspace, the National Guard of the United States sends fighter jets to investigate, and they fire on the craft when it doesn't respond. Activating a cloaking device too late, the spaceship crashes into the Atlantic Ocean, near Manhattan. The aliens aboard, Beldar Clorhone and his life-mate Prymaat, survive and quickly adapt to our human way of life, despite standing out with their conical shaped heads. Beldar was assigned by the Highmaster to conquer Earth as a Protoid Re-fueling Station under the title of 'Fuel Survey Underlord of the Wilderness Planet at the end of the Noctolium Solar Chain'. Beldar gets work as an appliance repairman, and when his grateful boss Otto discovers that Beldar has no documentation, he arranges for a false identity, which sends up a red flag that quickly alerts the Immigration and Naturalization Service. Meanwhile, after communicating with their world (Remulak) and discovering that a rescue vessel will not arrive for seven "Zurls" (many years), Prymaat informs Beldar that she is pregnant. They now need to completely adapt and safely blend in, in order to raise their child among humans. Ambitious INS agent Gorman Seedling and his assistant Eli attempt to capture Beldar and Prymaat, but they are able to elude the two agents.