These Are the Voyages...

Captain Alexander Richardson goes to one of the Batavia's holodecks to relive an event that has happened in the past on the Pegasus. The crew responds on a distress call out of Federation space, after which they start to investigate. A ship called the Nautilus drops out of warp, after which it destructs the wormhole with a photon torpedo. Soon after that, she self destructs. Fortunately, the Nautilus' captain, Velock, won't tell captain Richardson what's going on. The episode ends with a vague man, mentioned in the credits as captain Scott, who tells he will let the Federation pay for the mistakes they have made.