When members of the Romulan royal family are infected with a virus specially designed to attack their genetic code, suspicion immediately falls on the Federation.

With chaos threatening the Romulan Empire and a fragile peace at risk, Ambassador Spock offers the royal family the services of a specialist and friend: Dr Leonard McCoy. McCoy arrives on Romulus with Dr Beverley Crusher of the USS Enterprise-E, who has been investigating a similar virus since the incident that nearly killed her fellow-crew member Deanna Troi.

While Crusher attempts to track the virus to its source, McCoy seeks a permanent cure. To do so he will need to find a member of the royal family who has not been infected. Have they come too late? Not according to Lieutenant Commander Eric Stiles, the grandson of Helmsman John Stiles of the original Starship Enterprise.

He will lead Spock and McCoy on a mission to rescue the one uninfected member of the Romulan royal family, and come face to face with his past and his family''s ghosts.