The USS Tokyo is sent to investigate a strange reading from a system on the edge of the Neutral Zone with the fear that the Romulans might be plotting something again. On arrival the Tokyo's engines stall and the ship begins to drift. Without warning something very strange happens, the alternate mirror version of the Tokoy crew turn up.

The USS Tokyo and ISS Tokyo are caught in the same space time, trapped together but two crews. What will happen, will the two crews learn to work together or be trapped forever as they try and kill each other seeing each other as an invading force?