By David AdamsThe story“All you have to do,” says Martian humanoid Sab Than (Dominic West), “is marry me. With our two cities united, anything is possible.” He's speaking to Princess Dejah Thoris (Lynn Collins), daughter of the king of Helios (Ciaran Hinds), whose Martian city-state will soon be destroyed by Sab Than's rival city of Zodanga, if his daughter's politically-arranged marriage does not take place. Enter John Carter (Taylor Kitsch), an American Civil-War soldier, “telegraphed” from earth to Mars by a mysterious medallion. That's the set-up.Can Carter convince the 10-foot-tall, four-armed, green Tharks to join Helios and defeat Zodanga? Will Carter and Dejah fall for each other? How about Woola, the dog-like Martian pet that bonds with Carter? And who are the shape-shifting Thurns? What are they up to?The actorsTaylor Kitsch and Lynn Collins are attractive and plucky as interplanetary traveler John Carter and Martian Princess Dejah in this action/sci-fi/fantasy film of Edgar Rice Burroughs' 19th-century pulp novel “A Princess of Mars.” Adapting to Mars' low gravity, Carter discovers he can jump incredibly far and high. Tharks and humanoids want Carter and his athleticism on their side. “Will you stay and fight for Helium?” says earnest Princess Dejah. “I am not for hire,” Carter says in his matter-of-fact way. Lynn Collins, as Princess Dejah, is torn between loyalty to her father and her desire for independence.Dominic West (Sab Than), Mark Strong (Matai Shang) and Ciaran Hinds (King of Helios) play other humanoid characters. Willem Dafoe (Tars Tarkas), Thomas Hayden Church (Tal Hajus) and Samantha Morton (Sola) are performance-capture actors behind the principal Tharks. Daryl Sabara is young Edgar Rice Burroughs who provides the frame for the story. Cameos by Jon Favreau and David Schwimmer. Other comments“John Carter” is a gee-whiz, sci-fi adventure that will entertain if you don't worry a lot about the plot. Andrew Stanton directed. Stanton, Mark Andrews and Michael Chabon wrote the screenplay, based on Burroughs' novel. Plot themes — like a powerful ninth ray and lost gates that hold back Martian waters — are dropped in favor of battle scenes, some of which will remind fans of “Star Wars,” “Avatar” and “Planet of the Apes.” Like other sci-fi adventures, “John Carter” sometimes feels like a western — and is in its prologue with Apaches and cavalry. Often it looks like a sword-and-sandals epic. But don't worry about this stuff. It's just a movie — although, I read somewhere it cost $250 million to make.Rated PG-13 for intense action and violence, “John Carter” runs 132 minutes. 3-D doesn't add much. Fun for older kids and adults who remember being kids.Final words“John Carter” on Mars,Sci-fi, adventuresome —Far from a perfect flick,Still, it's lots of fun.