In my dream, I and a few others are on or near an ocean atoll or some similar island in a body of water. There is a dragon or sea monster there which we are trying to evade. After he has seen where I am, I swim underwater to try to move unseen. It is a struggle to avoid floating to the surface, and I hope that I'm deep enough not to be giving my movement away with ripples. It seems that I am successful.Later, having evaded the beast, I and one other person are sneaking along the seashore (no longer out at sea). I believe we were trying to remain unseen in some enemy's territory.