It's based on the book and includes Joe Estevez.

"Flatland: The Movie is an exciting half-hour animated film based on Edwin Abbott's classic novel. Flatland is an entirely two-dimensional world where different shapes live, work, and play--all under the rule of the evil Circles who are determined to keep the third dimension a secret, at any cost. The story follows Arthur Square (Martin Sheen) and his curious granddaughter Hex (Kristen Bell). When the mysterious visitor Spherius (Michael York) arrives from Spaceland, Arthur and Hex face grave danger as they begin to come to terms with the truth of the third dimension. Combining action, drama, geometry, and sociopolitical commentary, this moving story challenges audiences to grasp the limitations of their assumptions about reality and to think about the possibility of higher and previously inconceivable dimensions (both literal and metaphorical)." - Amazon.com description

How is this a movie?