Dr. Rebecca Gomperts sails a ship around the world, providing abortions at sea for women with no legal alternative. Her idea begins as flawed spectacle, faced with governmental, religious, and military blockade. But with each roadblock comes a more refined mission, until Rebecca realizes she can use new technologies to bypass law - and train women to give themselves abortions using WHO-researched protocols with pills. From there we witness her create an underground network of emboldened, informed activists who trust women to handle abortion themselves. Vessel is Rebecca's story: one of a woman who hears and answers a calling, and transforms a wildly improbable idea into a global movement.