Vessel begins with a young doctor, Rebecca Gomperts, horrified by the realities created by anti-abortion laws around the world. To challenge these inequities,  Gomperts provides abortions on a ship in offshore waters, but her project, Women on Waves, faces governmental, religious, and military blockades. But undeterred, Gomperts turns to new technologies to bypass the law—and trains women to give themselves safe medical abortions using WHO-sanctioned protocols with pills.