谁在那儿，轻声问候，心中涌动温暖的情愫。瑞瑞的视频丨vk

　　Everyone knows the feeling of anxiety when a stranger knocks on the door. Is it worth it to open? Who's there? A billionaire, an airplane pilot, a police trainee, a young mother and her daughter find themselves in the face of the unknown, they have to look beyond, and most importantly, inside themselves to understand what they are really afraid of.