The team completes their first underwater mission and are returned to Challenger Mountain, where they are confronted with the original Challengers team.
In an alternative London of the 1890s where computer technology is prevalent, Sebastian O escapes from an insane asylum to exact vengeance on the people who put him away.
When a bombing at a Promenade restaurant injuries members of different races, Odo is under pressure to find the perpetrator to prevent a diplomatic incident.
With Kahless and the Red Path in possession of the destructive power of the Crystalline Entities, Worf decides that they need someone who understands the Crystalline Entities...
