Demi-Tarif follows the low-key adventures of three young siblings, Romeo, Launa, and the youngest - Leo, left on their own in a rundown Paris apartment. One of them narrates, wistfully explaining how their mother abandoned them and calls them once in a while to see how they are doing or tell them she loves them. The three kids do as they please, roaming the streets, running out of restaurants without paying for food, and shoplifting from the local grocery store. They eat whatever and whenever they want, gorging themselves on sweets. They beg for change on the Metro and show up late for school in tattered, dirty clothes. All the while, they try to keep the fact that they are alone a secret from the world of adults.

A recent college graduate flees to Paris after a break-up, where his involvement with a prostitute begins to reveal a potentially dark recent past.

朱莉（露德温·塞尼耶 Ludivine Sagnier 饰）即将和未婚夫携手步入婚礼的殿堂，她乘坐上了从纽约飞往巴黎的飞机，心中满载着对于未来生活的幸福憧憬。让朱莉没有想到的是，在飞机上，坐在她身边的竟然是老相识安托万（尼古拉·巴多斯 Nicolas Bedos 饰）。朱莉和安托万之间有过一段为期3年的感情，但当时的安托万是一个十足的花花公子，他的不端行为让朱莉伤透了心，分手之后，朱莉发誓这辈子都不要和他产生交集了，哪知道造化弄人，在朱莉最幸福的时刻，他们重逢了。 实际上，安托万从来就没有忘记过朱莉，这意外的相逢更令安托万坚信两人之间的缘分未了。他决定利用这宝贵的7小时旅途，挽回前女友的心。