二十岁的大卫是个活在当下的空想家，没有固定工作以打散工糊口。他邂逅了刚移居巴黎的莲娜，很快便堕入爱河。但没多久之后，他平静的生活却因姐姐在一次袭击中猝然身死而突然终断。在震惊和伤痛之余，大卫还发现自己要独自照顾七岁的侄女阿曼达。

Every year, 310 killings in France go unsolved, leaving the victims' crushed families in a state of endless grief. The French judicial system is implacable: there's no money to continue investigating cases that lead nowhere. Hunting down murderers to help bereaved families get justice is more than just a job, it's a duty for Thomas Bareski, a retired, hotshot police detective. A wandering, footloose, nature-loving soul who lives out of his van, Thomas Bareski isn't just a one-of-kind man, he's also an extraordinary police officer who's ready to upend his way of life to fulfill his mission.