(Decker and McCoy enter the bridge. The viewscreen shows a cone shaped object in profile.
Spock: It looks very much like Commodore Decker's planet killer. And it is pursuing us.
(The object turns to face the Enterprise.)
Spock: We are more manoeuvrable, but it is gaining on us. Sensors indicate some kind of total conversion drive.
[Constellation Auxiliary Control]
Spock: No evidence of life, subspace interference level incredibly high.