电影《世上最美的离别》改编自韩国作家卢熙庆的同名原著及电视剧。卢熙庆因怀念自己因癌症去世的母亲而写就这本小说中刻画了一个平凡又伟大的母亲的一生。
母亲（裴宗玉 饰）在婆婆身患老年痴呆后辛苦照顾她15年，只身挑起家中重担，为一家人操劳不休。而丈夫（金甲洙 饰）对家事丝毫不关心，女儿爱上了有妇之夫，儿子也面临着高考的艰难形势。家庭中的每个人似乎都有各自的烦恼各自的事情。她去丈夫上班的医院看病，丈夫却因为自己是一名薪资低的医生而不愿意在工作的地方见到她；她去看上班的女儿，想约她一起吃一顿午餐，哪怕只是简单的一碗乌冬面，而女儿却忙着和情人约会，推脱她；她心疼的儿子，考上了大学一身轻松，和女朋友约会喝酒，过自己的快意生活。而她却在此时被查出患有膀胱癌，并处于癌症末期的情况下。在发现母亲即将离世时，家中每一个人的态度都发生了改变......

A film director who no longer makes films arrives in Seoul to meet a close friend. When the friend doesn't show up, he wanders the city aimlessly for three days, grabbing drinks and meeting women, with each day playing out like a version of the last.

Having died unexpectedly, firefighter Ja-hong is taken to the afterlife by 3 afterlife guardians. Only when he passes 7 trials over 49 days and proves he was innocent in human life, he’s able to reincarnate, and his 3 afterlife guardians are by his side to defend him in trial.

An aging poet summons his estranged sons to the hotel he is staying at because he feels his death is near; meanwhile, he encounters two women staying at the hotel.

Hae-won, a college student, wants to end her secret affair with her professor, Seong-jun. Feeling depressed after bidding farewell to her mother who is set to immigrate to Canada the next day, Hae-won seeks out Seong-jun again after a long time. That day, they run into her classmates at a restaurant and their relationship gets revealed. Hae-won gets more agitated and Seong-jun makes an extreme suggestion to run away together.