Cloak and Dagger (Star Trek: Voyager) (Dark Matters)

Cloak and Dagger is the nineteenth book in the main Star Trek Voyager series. It is also book one in the Dark Matters mini series.
==Book Description==
Allying with a mysterious and powerful alien species, the Romulan Empire from 20 years in the past has created a new wormhole -- one leading straight to the present-day Delta Quadrant and the U.S.S. Voyager. There a sinister plan is set in motion, as the Romulans wish to gain a head start on future Federation technology by capturing Voyager and manipulating the phenomenon known as "dark matter"...with potentially disastrous consequences for the entire cosmos.
(Description from Amazon.com)