Star Trek V: The Final Frontier

Captain Kirk and his crew must deal with Mr. Spock's long-lost half-brother who hijacks the Enterprise for an obsessive search for God at the center of the galaxy.
The crew of the Federation starship Enterprise is called to Nimbus III, the Planet of Intergalactic Peace. They are to negotiate in a case of kidnapping only to find out that the kidnapper is a relative of Spock. This man is possessed by his life long search for the planet Sha Ka Ree which is supposed to be the source of all life. Together they begin to search for this mysterious planet.