There is one. It's decent, but it doesn't quite live up to the imagination and depth of the original novel. The illustrations are nice, but the story's complexity could have been handled better.
It's not easy to find it for free online. Most legitimate sources require you to purchase or have a subscription. Maybe check your local library for borrowing options.
The main characters are Meg Murry, her brother Charles Wallace, their friend Calvin, and their father. There are also the three celestial beings - Mrs. Whatsit, Mrs. Who, and Mrs. Which.