In 2374, Rekar led a successful hijacking of the Federation starship USS Prometheus under orders to bring it to the Romulan military on Romulus, however, he was actually working for the Tal Shiar. He and his team killed the Starfleet crew and fought off the pursuing USS Bonchune using the Prometheus' experimental multi-vector assault mode, despite the fact that it hadn't yet been tested. After the Bonchune was disabled, Rekar ordered the ship navigated toward the Empire, however, en route, he ordered the heading changed to a Tal Shiar fleet, surprising his team.
Unbeknownst to him, The Doctor had been transferred from the USS Voyager and made plans to stop him along with the Prometheus' EMH Mark II. Rekar accepted that The Doctor was doing medical scans until he accessed a console. Rekar detained and attempted to interrogate him, but he and the other Romulans were rendered unconscious by neurozine gas, introduced into the ventilation system by the EMH Mark II. He was unconscious and captured when the vessel was then returned to Starfleet control. (VOY: "Message in a Bottle")