What is the plot of A Wrinkle in Time?

In
, the Murrys miss their father, who is a scientist who has mysteriously
disappeared. At the same time, the lead character, Meg Murry, deals with the problems of
adolescence. She feels she is an awkward and unattractive misfit and also feels she has to
defend her little brother, Charles Wallace, from those who think he is strange.

On a dark and stormy night, a mysterious stranger, Mrs. Whatsit, shows up at the
Murry's New England farmhouse. Charles Wallace has been expecting her. As it happens, she and
her two companions, Mrs. Which and Mrs. Who, can take Meg, Charles Wallace, and Meg's handsome
friend Calvin to the planet Camazotz, where their father is being held prisoner. Once there,
they can try to free him.

Camazotz is wholly evil and controlled by an
entity called IT that tries to take over the...