Rock and a Hard Place (Star Trek Next Generation 10)

Under the best circumstances, terraforming is a tough, dangerous task that pits the hardiest of pioneers against an unforgiving environment. When the terraformers on the planet Paradise fall behind schedule, commander Riker is given temporary leave from the U.S.S. Enterprise(TM) and sent to assist. Riker's replacement on the Starship Enterprise is a volatile officer named Stone whose behavior soon raises questions about his ability and his judgment. Meanwhile, Commander Riker has become enmeshed in a life and struggle with Paradise's brutal landscape. However, he soon learns that not all of the planet's dangers are natural in origin -- as he comes face to face with Paradise's greatest danger and most hideous secret.