Lucía loves the way Lucas smiles, the new boy in her class, smiles. She immediately approaches him because she thinks it must be hard to arrive in a new place where everything and everyone is unfamiliar, but as the days go by she notices that Lucas has grown close to Fran and his gang. This surprises her as they are complete hooligans. But Fran can't really be Lucas's friend because he does things to him that a friend would never do. And the worst thing of all is that Lucas's amazing smile is gradually disappearing.