No Choice.

Art by Jetfreak 7(original title Fighting The Enemy).
The tale below may change as currently I'm all drugged up and brain is very fuzzy.

Captain's Log Supplemental.

Four hours ago we were attacked by a large vessel that suddenly appeared in our path from out of a dimensional rift.  All attempts at Communications were ignored and we were soon in a desperate battle which we came close to losing.
The enemy weapons were of an unknown type, just like their ship, and our shields were soon on the verge of collapse, with multiple hull breaches being reported.  We lost fifty two crewmembers to decompression before the emergency forcefields activated... twelve are unaccounted for...Pause Log.

Resume Log Entry.

We fought back, causing significant damage to the enemy ship only with our quantum torpedoes, which their shields had trouble repelling.  Then our Warp drive was knocked out as was our main impulse engine. Lt. Grange managed to prevent us from going into an uncontrolled spin using the nacelle impulse units and rcs thrusters, and we struck a lucky hit, knocking out their shields, with our last quantum torpedoes.
I tried to communicate with them again, but all we got back was a garbled response, something about us invading their dimension.
Cmdr. Xon then reported that the enemy ship was locking all it's weapons onto our Warp Core.  Faced with no alternative, I gave the order to lock onto their main power source and fire.
The enemy ship withstood the barrage of torpedoes and phaser fire for a few moments, but without their shields to protect them the end was inevitable.  The ship exploded, and scans have revealed no survivors.
As repairs continue I am left with some troubling questions.  What is this invasion they were talking about, where did they come from, and will they return?