An excellent prequel that basically tells the origin of the original Star Trek series and how its crew came together.
About 25 years ago, Kirk's father, George Kirk, assumed control of his ship when the Captain left to board a Romulan ship; they were under attack from the much larger ship. Kirk evacuates everyone, including his pregnant wife, who soon gives birth to James T. Kirk. As a result, George Kirk saves hundreds of lives. George dies soon after that, while sacrificing himself.
The core of the story is the lives of James T. Kirk and Spock. They are the only two characters who are followed from childhood to adulthood. As children, they were both very much like they are as adults. Kirk is a risk-taker, who seems to always be in the right place at the right time. Spock is half-vulcan and half-human, often being torn between the two. When they first meet, and for some time after, Kirk and Spock don't get along; in fact, they don't even like each other. Later, they develop a friendship and mutual respect for each other. I especially got a kick out of seeing a younger McCoy, Uhura, Scotty, Sulu and Checkov, who was only 17 when he joined the Enterprise crew.
James T. Kirk assumes control of the Enterprise in much the same way his father did his ship. Christopher Pike is the current captain. He boards the Romulan ship, which is destroying the planet Vulcan with a device that creates a black hole within the planet, thereby destroying it. The Romulan captain, Nero, is the same one who attacked George Kirk's ship. Pike leaves Spock in charge, because he is currently first officer. Spock in turn makes Kirk first officer. Eventually, it is necessary for Kirk to assume control. (I don't want to give away the details of how this all happens).
I had heard that Leonard Nimoy, the original Spock, makes a "cameo", but his role is actually more integral to the story than that.
Content(and SPOILER) warning : Not as risque as the previews would lead you to believe, but there is a scene where Kirk is in bed with Uhura's roommate. When Uhura returns, Kirk jumps up and you can see that the girl has a bra and underwear on. Then Kirk hides under the bed, and you see Uhura undressing. There is no nudity; all you see is her underwear and bra also. I felt that this scene was NOT necessary; they could have easily made the movie without it.
An EXCELLENT movie...see it!