The Wounded Sky

Summary
From the back cover: A pretty alien scientist invents the Intergalactic Inversion Drive, an engine system that transcends warp drive and the 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.

Now Captain Kirk and his friends face their greatest challenge - to repair the fabric of the Universe before time is lost forever!