The Enterprise crew travels back in time to prevent an alien probe destroying the Earth. The only thing that can avert the disaster is a humpback whale, a creature extinct in the 23rd century - but adjusting to life back in 1986 proves a distinct challenge. Sci-fi adventure sequel, starring William Shatner, DeForest Kelley and Leonard Nimoy, who also directed.

When a huge alien probe enters the galaxy and begins to vaporize Earth's oceans, Kirk and his crew must travel back in time in order to bring back whales and save the planet.