A Wrinkle in Time by Madeleine L'Engle, 1963

Setting: The Murry residence near a forest, somewhere in small town, USA. Also, different worlds like Uriel, populated with creatures like winged centaurs; Camazotz, a Dark Planet, held by an evil IT; Ixchel, an opaque populated by gentle creatures with no eyes and tentacles for ears and hair; a two-dimensional planet. Time period: No particular time period, especially since most of the action is in Kairos (an added section in the book explains: real time, pure numbers with no measurement). This is in contrast to Chronos (ordinary, wrist-watch, alarm-clock time, explained in the same section). The length of the journey could have been centuries or five minutes, as they were travelling in a wrinkle time as well as a wrinkle in space. Main character(s): Margaret "Meg" Murry, an awkward teenager, story told from her POV. Charles Wallace Murry, Meg's five-year-old brother. Calvin O' Keefe, a popular boy from Meg's school. Guardian angels? Witches? Higher beings?: Mrs. Who, Mrs. Which and Mrs. Whatsit. IT: Evil incarnate. Winner of the 1963 Newbery Medal.

The plot: For Meg Murry, life sucks: her grades are dangerously low, her hair unmanageable and her temper mercurial. All this because her father is away, hasn't written for a year and the town grapevine says he has gone off with another woman. Why can't Meg handle all this as gracefully as her beautiful, scientist-mother does? Meanwhile, Charles Wallace, Meg's brother, has taken to talking with strangers living in a haunted house in the forest. These strangers (and they are very strange indeed), know where their father is and that he is in danger. It is up to Meg, Charles, and Calvin, a boy they meet near the haunted house, to rescue Dr. Murry. An evil force holds Dr. Murry captive in Camazotz, a planet far, far away. The strange ones, Mrs Who, Mrs. Which and Mrs. Whatsit tesser (pass through a wrinkle in time) the children into Camazotz and give them gifts to help them take Dr. Murry away from IT, the big brain that controls all activity in the planet. And when I say "brain," I do not mean the plotter of a scheme or the smart person behind a crime. I do mean BRAIN. In all its convoluted, gray-matter glory. The rescue operation is botched and it is up to Meg, with all her faults and fears and insecurities to make everything right.