电影讲述了长安城被一场突如其来的浓雾瞬间淹没，众人惊慌失措四处逃散。不良人萧城守护着孱弱太子，与平民一起被困，等待雾的消散。然而，浓雾并没有如期散开，而走进浓雾的人也一去不返，浓雾里惊天怪兽逐渐露出狰狞面目，萧城为守护长安，拼死一搏......

In the late nineteenth century, Ellen Creed works as the live-in companion to Miss Leonora Fiske, a retired actress who lives in the English countryside and who still retains her theatrical mannerisms. Ellen receives notice that the landlady of her two sisters, Emily Creed and Louisa Creed, who currently live in London, is threatening to call the police to haul them away to an asylum because of their disruptive behavior due to their mentally deranged state. Ellen will not allow her sisters to be institutionalized, and convinces Miss Fiske to allow them to stay with them for a couple of days. Miss Fiske was unaware of their deranged mental state when she agreed and is also unaware that Ellen hopes to make their stay permanent. Both issues eventually become apparent to Miss Fiske, who cannot tolerate how Emily and Louisa disrupt her home life. However, Ellen "convinces" Miss Fiske to take an extended leave from the house, while Ellen tells her sisters that she bought the house from Miss Fiske, which the sisters are not to tell anyone else. The secrets that Ellen is keeping about the situation threaten to bring her and her sisters' lives down when they receive a visit from their distant nephew Albert Feather, a cad who has his own financial well being as his main priority.

倪雾带女儿就医，在医院重逢前男友裴淮聿。因倪雾改头换面，导致裴淮聿未认出。同学会上传她“死讯”，他调查发现与倪雾似有过往。慢慢接触中，裴淮聿疑窦丛生，最终知晓原来程青渺就是倪雾，女儿竟是自己亲生，两人终拨开迷雾，解开心结。

倪雾带女儿就医，在医院重逢前男友裴淮聿。因倪雾改头换面，导致裴淮聿未认出。同学会上传她“死讯”，他调查发现与倪雾似有过往。慢慢接触中，裴淮聿疑窦丛生，最终知晓原来程青渺就是倪雾，女儿竟是自己亲生，两人终拨开迷雾，解开心结。

电影《长安·长安》以中欧班列长安号为载体，以2023年“一带一路”倡议提出十周年为时间节点，讲述了2031年发生在“长安号国际旅游专列”上的跨国故事。

患了一种罕见失忆症的年轻的伟，正尝试从家人朋友口述回忆中努力寻回自己的过去。动荡不安中，伟发现对自己过去隐藏着的重要线索，最后决定面对后果。「雾」片随伟漂流于正处于历史的十字路口的香港，展开一场自我发现与救赎的旅程。

患了一种罕见失忆症的年轻的伟，正尝试从家人朋友口述回忆中努力寻回自己的过去。动荡不安中，伟发现对自己过去隐藏着的重要线索，最后决定面对后果。「雾」片随伟漂流于正处于历史的十字路口的香港，展开一场自我发现与救赎的旅程。

一个男人（冢本晋也 饰）从昏迷中醒来，突然发现自己置身于一间昏暗类似迷宫的房间（地下室）里，关于自己的一切完全没有头绪，记忆尽失。是幻觉，还是恶…