The Dama Tower Defense Mechanism was a ship defense system used by the
Dama several thousand years ago. It was installed on each Dama ship. It served as a basic defense which absorbed energy propelled at its shields.
The DTDM prototype was flawed, though. The DTDM's easily took a life of their own as a result of their nanotechnology. The defense protocol became alive and started spreading. Every copy of the DTDM/Tower Virus was destroyed...
Every copy except for one. One which was installed on a ship... A ship which went missing.