Romulan research ship that tested an experimental interphase generator in 2368, leaving Ro Laren and Geordi La Forge out of phase.
The Romulans operated science vessels for research in the 24th century. In 2368 one of these ships was secretly testing an experimental interphase generator, a device meant to let a ship move undetected, out of phase with normal matter.
In The Next Phase, the Enterprise-D answered its distress call after an explosion aboard. A transporter accident on the return left Ro Laren and Geordi La Forge out of phase and invisible to the crew, who believed them dead. The two uncovered a Romulan plan to destroy the Enterprise when it next went to warp and found a way to make themselves seen.