The Return (Star Trek)

Veridian III: A world has been saved, the U.S.S. Enterprise 1701-D lies in ruins, and one of the galaxy's greatest heroes rests beneath a simple cairn of rocks on a lonely hillside. But as a legendary Vulcan ambassador comes at last to the grave of his best and dearest friend, the adventure is only beginning.
The Borg and the Romulan Empire have joined forces against the Federation, and their ultimate weapon is none other than James T. Kirk, resurrected by alien science to destroy the Borg's most formidable enemy: Jean-Luc Picard.