Hmmm. McCoy is accused of causing a plague and forced to go on trial: good. The alien is fooled into sneaking on board the Enterprise by leaving the shuttle bay doors open: bad. Post-apocalyptic looking planet: good. No one remembers to exercise basic quarantine procedures on leaving a planet covered with plague: bad. Funnily enough, in the end it turns into an episode of House, with McCoy realising that one of the symptoms needs to be ignored. Not fantastic, again a case of an episode with a concept more ambitious than the execution.
99 down, 638 to go.