Dark Vengeance — E.R. Mason

It was to be a luxury cruise to the planet Enuro for the purpose of bringing the newly refit Starship Electra back to Earth. For Adrian Tarn, and R.J. Smith the trip was a long overdue vacation until someone or something began murdering the guests. As the two struggle to understand what is happening, they discover the situation is actually much worse than anyone realizes. The only question remaining is; do you dare join them aboard the Starship Star Seven? (Standalone, 4th book in the Adrian Tarn series)