A Promellian battle cruiser, a relic of a 1000-year-old war, snared the Enterprise-D in a booby trap, the same trap which the battle cruiser itself fell victim to.

During the Promellian-Menthar War, the Menthars used Aceton assimilators to modify and convert a ship's energy into harmful radiation, which the Menthars would then use to bombard their enemies. Hiding the assimilators within the ruins of Orelious IX, the same ruins where Enterprise found the Promellian vessel, the Menthars created a booby trap from which no ship could escape.

However, Geordi La Forge used Holodeck simulations to save Enterprise from the Promellian ship's fate.

Found with its Lang-cycle fusion engines still intact, the battle cruiser was destroyed by Enterprise's photon torpedos, thus preventing future starships from getting caught in the trap.

Captain Picard commented that he once built model ships in bottles, and one of those ships was a Promellian battle cruiser.