A Wrinkle in Time (Time Quintet, #1)

Megg Murray, her little brother Charles Wallace, and their mother are having a midnight snack on a dark and stormy night when an unearthly stranger appears at their door. He claims to have been blown off course, and goes on to tell them that there is such a thing as a "tesseract", wich, if you didn't know , is a wrinkle in time. Meg's father had been experimenting with time-travel when he suddenly disappeared. Will Meg, Charles Wallace, and their friend Calvin outwit the forces of evil as they search through space for their father?