There is just one little problem. Mr. Hopgood, the American millionaire, is buying the castle for his daughter, whom he adores. But she is recovering from polio, and he worries about anything that might frighten her. So he makes Alex promise that the castle has no ghosts before he signs the paper. Alex promises...but now he has to find a new place for his beloved ghosts to live.
There's Krok, a Viking warrior; Uncle Louse, who was once a vampire but now is old and, to his eternal shame, has no teeth; Miss Spinks, a governess who constantly tries to drown herself; five-year-old Flossie, a poltergeist; and Cyril, a hellhound with enormous eyes, a drooping belly, and a very long ghostly body. All these ghosts are like a family to Alex, and it is with an aching heart that he sends them off to live with his aunt in her mansion - along with her disapproving, snobbish ghosts - and heads off to boarding school.
Once at school, Alex doesn't know that Cyril runs off from Dunloon, having been scolded by the snooty ghosts for bringing his favorite toy, a wonderfully smelly dead ferret, into the house to be sat upon by Alex's uncle. Nor that the ghosts run off after Cyril, and arrive at Carra only to find that the castle has been knocked down. Or that the ghosts fall asleep among the stones of the castle, only to wake up on a ship to learn that Carra is being transported to Texas to be rebuilt.
Alex is invited by Mr. Hopgood to come to Texas while Carra is being put back together, to make sure that everything about the castle is just as it was in Scotland. Alex is delighted - and he and Helen, Mr. Hopgood's daughter, become friends. They are looking forward to Carra's completion - but there is a plot afoot to kidnap Helen, and three very despicable villains are behind it. As the construction on the castle moves forward, so do the kidnappers' nefarious plans...
CREEP stood for the Council for the Re-Education of the English People. The loonies who belonged to it wanted Britain to be run like a police state with everyone marching about in uniforms and being flogged if they didn't obey the rules. CREEP wanted to get rid of dogs because they made a mess, and they wanted to get rid of the queen because she kept talking about peace and goodwill, whereas what CREEP wanted was a blood-thirsty war to make Britain great. (They thought that wars were good for people.) There were a lot of things that CREEP wanted to get rid of: old people, because they weren't any use, and pop concerts, and vegetarians. And like all people with mad ideas, they started by throwing bombs.