Rogue Saucer

Repairs to its own saucer section leave the Enterprise-D testing an experimental replacement, one supposedly built to survive a full planetary crash landing, in theory. Riker, Data, Worf, and La Forge run the trial alongside Admiral Nechayev, and theory turns into crisis when hostile forces seize the new saucer mid-test and turn it into a weapon against the ship it was built to serve.