Carbon Grey Omnibus Collection

"The Sisters Grey -- beautiful, deadly -- warriors sworn to protect the Kaiser, ruler of Mitteleuropa. But as a great war rages, the Kaiser is found dead, and one sister -- Giselle Grey -- is accused of his murder. Pursued by her enemies across the battlefields of Mitteleuropa, Giselle must unravel the prophecy of the Carbon Grey -- before history itself is rewritten"--Page 4 of cover.