Green aliens, the original residents of the earth, are temporarily living in Greenovia, a planet at the edge of the great black hole. They are concerned that with the way humans are treating the planet, there might not be anything left of it when they will return. To figure why humans are not taking care of their planet, they send a spy to live on earth as a human being. The mission goes wrong, however, and disrupts the romantic life as we know it. The alien romance, however, turns to be a key in understanding the humans' plan for the environment.