Returning from a hunting trip in the forest, the Henderson family's car hits an animal in the road. At first they fear it was a man, but when they examine the "body" they find it's a "bigfoot". They think it's dead so they decide to take it home (there could be some money in this). As you guessed, it isn't dead. Far from being the ferocious monster they fear "Harry" to be, he's a friendly giant.
The fate of the galaxy rests in the hands of bitter rivals. One, James Kirk, is a delinquent, thrill-seeking Iowa farm boy. The other, Spock, a Vulcan, was raised in a logic-based society that rejects all emotion. As fiery instinct clashes with calm reason, their unlikely but powerful partnership is the only thing capable of leading their crew through unimaginable danger, boldly going where no one has gone before. The human adventure has begun again.