Nero is NOT just a Romulan. He's the REAL Emperor Nero, from ancient Rome. As crazy as it sounds, it's true. He's brought to the future and takes control of the Romulan people (who aren't called Romulans at first) and models their society after Imperial Rome.
He longs for Earth, and believes his Empire is even greater there since so many years have past by, and insists it possible that his love is still alive, somehow.
He finds out that he and his fleet are defeated in battle by starfleet, so he alters the timeline by, you guessed it, killing Winona Kirk.
This sends ripples through the timeline, and, you guessed it again, old Spock, now living on Romulus, POST TNG by about 40 years finds out and travels back to set everything right.
There's a scene similar to Star Trek IV, except this time he's being chased by Romulan vessels when he goes around their star. They do not follow.
Also, Nero doesn't die in the end, which is a relief to many script junkies. He's apparently not just another carbon copy disposable bad guy.
He longs for Earth, and believes his Empire is even greater there since so many years have past by, and insists it possible that his love is still alive, somehow.
He finds out that he and his fleet are defeated in battle by starfleet, so he alters the timeline by, you guessed it, killing Winona Kirk.
This sends ripples through the timeline, and, you guessed it again, old Spock, now living on Romulus, POST TNG by about 40 years finds out and travels back to set everything right.
There's a scene similar to Star Trek IV, except this time he's being chased by Romulan vessels when he goes around their star. They do not follow.
Also, Nero doesn't die in the end, which is a relief to many script junkies. He's apparently not just another carbon copy disposable bad guy.