After an accident in Engineering leaves Trip mortally injured, Dr. Phlox attempts to save the chief engineer by creating a "mimetic simbiot" ? a clone ? of him to harvest neural tissue from it. In its very short lifespan, the simbiot grows rapidly from baby to adult, and surprises the crew with detailed memories of the real Trip's life. Meanwhile, the accident has left Enterprise disabled and adrift inside a destructive space cloud, so the crew attempts to free the ship before they are stranded forever.
