The terse encrypted warning came from one of the picket patrols
To: HEF Command
Message: Tyrannid troop movements detected in our sector. Co-ordinates are being transmitted via secure channel.
The reposnse was equally brief.
From: HEF Command
Message: Understood. Shadow enemy forces, do not engage. Repeat: do not engage. Independant direct action will be taken.
Shas'O Tyrnax considered his options. This will need more than a simple patrol...