In-Universe:
The U.S.S. Defiant NX-74205, and a good portion of the Alpha quadrant fleet, is destroyed by the Dominion fleet thanks to the Breen energy dampening weapon.
Production:
This is the third version of the CGI Defiant from Digital Muse. The most telling visual element to me is the front deflector. It's supposed to be a smooth consistent curve, but in this version the top is more flat and then there is a definite 'bend' and then it curves.
