Siblings, it is said, are the only people we truly spend our entire lives with. Perhaps that longevity explains the unique and edgy dynamic that brothers and sisters carry through their relationships. In Asteroid, siblings Mauricio and Cristina were part of a tragic as teenagers, and they have been struggling ever since. Now adults, Mauricio is still living in the childhood home where they grew up, proudly holding on to the hard-fought, twin successes of having both a girlfriend and stability as a sober recovering alcoholic. Then Cristina shows up, absent after seven years, fleeing her latest flame-out in Madrid. Her emotional instability brings disastrous consequences for both of them, leading to think that some people should simply never get back together.