Meg Murry and her friends become involved with unearthly strangers and a search for Meg's father, who has disappeared while engaged in secret work for the government.

Polly's visit to her grandparents in Connecticut becomes an extraordinary experience as she encounters old friends and mysterious stangers and finds herself traveling back in time to play a crucial role in a prehistoric confrontation.

With Meg Murry's help, the dragons her six-year-old brother saw in the vegetable garden play an important part in his struggle between life and death.