The Wounded Sky (Star Trek: The Original Series, #13)

An alien scientist invents the Intergalactic Inversion Drive, an engine system that transcends warp drive, and the U.S.S. Enterprise will be the first to test it! The Klingons attempt to thwart the test, but a greater danger looms when strange symptoms surface among the crew, and time becomes meaningless.

Captain Kirk and his friends must repair the fabric of the Universe before time is lost forever.