The Enterprise was in a (dark matter?) nebula that caused parts of the ship to occasionally become (in Trek's terms) "phased" hull breaches were reported, a crew-member was phased through, and bisected, through the deck. They eventually found a way to track and detect these anomalies in the nebula and used a shuttle (piloted by Picard) to detect the anomalies ahead of the ship and send directions back to the Enteprise which way to turn before colliding with one. (I think the shuttle's smaller profile made it easier for this process than the ship's don't recall why.) Eventually the shuttle nicks one of the anomalies, screwing up its engine, putting into an uncontroles spin, Picard is beamed off the shuttle just before it explodes, the Enterprise gets out of the nebula and lives on to fight another day.