The Pegasus

Admiral Erik Pressman, Riker's former captain, joins the Enterprise to find the wreck of the USS Pegasus, a ship believed destroyed while Riker served aboard as a young officer. Pressman orders Riker to keep the mission's true purpose from Picard. With a Romulan warbird shadowing the search, the Pegasus is found lodged deep inside an asteroid near the Neutral Zone. Riker finally admits that the crew mutinied against Pressman during a warp core crisis, and that he stood with his captain. Picard discovers the Pegasus carried a prototype phasing cloaking device, built in violation of the Treaty of Algeron, and that Starfleet Intelligence buried the inquiry. When the Romulans seal the Enterprise inside the asteroid, the device carries the ship straight through solid rock. Picard then decloaks in full view of the Romulans and has Pressman arrested. Riker insists on facing arrest too, and Picard tells him his eventual honesty proves he deserves his post.