Star Trek IV: The Voyage Home

Star Trek IV The Voyage Home is a 1986 American science fiction film released by Paramount Pictures. It is the fourth feature film based on Star Trek, and is a sequel to Star Trek III The Search for Spock 1984. It completes the story arc begun in Star Trek II The Wrath of Khan 1982 and continued in The Search for Spock. Intent on returning home to Earth to face trial for their actions in the previous films, the former crew of the USS Enterprise finds the planet in grave danger from an alien probe attempting to contact nowextinct humpback whales. The crew travel to Earths past to find whales who can answer the probes call.

In 2286, a large cylindrical probe moves through space, sending out an indecipherable signal and disabling the power of ships it passes. As it takes up orbit around Earth, its signal disables the global power grid and generates planetary storms, creating catastrophic, sunblocking cloud cover. Starfleet Command sends out a planetary distress call and warns starships not to approach Earth.On the planet Vulcan, the former officers of the USS Enterprise are living in exile after the events of Star Trek III The Search for Spock. Accompanied by the Vulcan Spock, still recovering from his resurrection, the crewexcept for Saavik, who remains on Vulcantake their captured Klingon BirdofPrey starship nicknamed the Bounty, after the Royal Navy ship and head to Earth to face trial for their theft and destruction of Enterprise. Hearing Starfleets warning, Spock determines that the probes signal matches the song of extinct humpback whales, and that the object will continue to wreak havoc until its call is answered. The crew uses their ship to travel back in time via a slingshot maneuver around the Sun, planning to return with a whale to answer the alien signal. ........

Source: Wikipedia