安东尼奥（Antonio Ferrandis 饰）是一名德高望重的西班牙作家，常年定居于美国。一辈子勤勤恳恳写作的安东尼奥，终于攀登上了职业的最高峰，获得了诺贝尔奖学金。可就在人生最辉煌的时候，上帝给他开了一个小玩笑，安东尼奥发现自己患上了绝症，生命只剩下短短的几个月了。
在人生最后的几个月里，安东尼奥决定返回阔别已久的故乡西班牙，在那里，安东尼奥和四十年前的恋人埃伦娜（Encarna Paso 饰）重逢了，曾经，残酷的战争令他们被迫分离，想不到再见面的时候，两人都垂垂老矣。然而，这段缘分显然已无再续的可能了，临别时，埃伦娜送给了安东尼奥一个意外的礼物。

Manuela and Olmo meet again in a future as they had promised fifteen years earlier as teenagers, when they lived their first love.

Quién lo impide is a call to change our perception of adolescents and youths; our idea of those born in the early 21st century who have recently reached adulthood; those who now seem guilty of everything as they themselves see their hopes dashed. Somewhere between documentary, fiction and pure testimonial record, the young adolescents show themselves the way they really are, the way we rarely see them, or the way they let us see them: taking advantage of the film camera to show off the best of themselves and renew our trust in the future; from fragility and emotion, with humour, intelligence, beliefs and ideas. Because the young people who speak to us about love, friendship, politics or education refer not only to their own situation, but to the things that always matter to us, at any age. Quién lo impide is a film about ourselves: about what we were, what we are and what we will continue to be.