Flattened

Our Earth is round. Gravity keeps everything anchored to the ground; it keeps everything from floating away. It has an axis, and two magnetic poles. One is in the north, at the top of the world, and one is in the south, at the bottom. On our Earth, we discovered that by sending someone to sail off the edge of the Earth, it usually just meant a long voyage to the other side of the world. Their Earth is flat. True, gravity is still present in their land. Almost everything feels its pull; almost everything is tethered to the ground. There are no magnetic poles, for there is no top or bottom of their land. When they are sent to fall off the edge of the Earth, that is precisely what happens. Gravity has no pull on the water that pours off the edge of the Earth. So when our four main characters, all lives that were never expected to collide, are all put on the same ship to fall off the edge of the Earth, what could possibly happen? Could they end up in some strange paradise, or an undying inferno?