John Carter (Taylor Kitsch) is a Civil War veteran who has lost everything, and has gone West to seek his fortune. Somehow, he's gotten wind of a "cave of gold," and that's what he's after. He finds it, but after killing a man -- a Thern, a race who have a strange and fairly unwholesome involvement in the decline and fall of civilizations -- who's trying to kill him, he finds himself transported to a strange place where he is taken captive by a race of very tall, skinny, green four-armed people, the Tharks. He is given a drink of something by a woman named Sola (Samantha Morton) that enables him to understand the language. He soon falls in with Dejah Thoris (Lynn Collins), a princess who is fleeing an unwanted marriage with Sab Than (Dominic West), the ruler of Zodanga, a rival city that has been engaged in a civil war with her home city of Helium for a thousand years and is about to win. The marriage is the price of peace. Turns out Carter is on Barsoom (Mars), and winds up inextricably involved in the civil war, in spite of starting out just trying to get home. Things are complicated by the interference of Matai Shang (Mark Strong), the leader of the Therns who has his own plans for the people of Barsoom.
And that is a really bare-bones summary. It's a complex milieu and a very intricate plot. After that, where to start?
OK -- the Martians, in their infinite variety. The Tharks, who are humanoid but certainly not human -- physically, at least -- are very well executed. The animatronics are of a very high order, very lifelike, and this carries through to the native animals. The voice actors, who in addition to Morton include Willem Dafoe as Tars Tarkas, Sola's father and the "emperor" of the Tharks, bring them to life.
The actors who portray the humans are equally good, but in some places they're fighting a script that veers into bombast and is sometimes incomprehensible. (Although I didn't find as many WTF? moments as some writers have claimed.)
Yeah, it's not the greatest heroic fantasy film out there, but it's worth watching. Of course, one reason I like is probably this:
For full credits, see IMDb.