12 teenagers show up at an abandoned hospital. As prescribed, they enter the building, open safe containing, take one of numbered tags from 1 to 12, and head to a "designated place". None of them have ever met before, but all of them in despair with their lives and come up with one common goal: to euthanize themselves. But upon arrival in the room, they find that one young man is already occupying on one of the 12 prepared beds.

Who is he? Was it a suicide? Was it murder? Should they proceed anyway? And is there a murderer amongst them?

According to the preset rules of the gathering, the members must take a vote and unanimously agree to proceed. But the unexpected turn of events compels them to hold a discussion and assess each other to solve the mystery before they can go ahead with their original plan.

In the process, however, the reasons for each of them choosing to die come to light, leading to a final decision. The question is: What is the real purpose of the gathering?

12个孩子来到一家已经废弃了的医院。
进入医院，打开金库，里面摆放着1到12的数字卡片。聚集到这里的12个人，每个人拿起一个数字，走向"集合点"。
这些心灵受创的第一次见面的孩子们的目的是想要大家一起安乐死。
可是，"集合处"的床上，已经有一个孩子躺倒在其中。
他是谁。自杀，还是他杀。仍按原计划进行吗。说不定犯人就在其中。
聚集在此的规定是"全体一致"，孩子们决定少数服从多数。
在出乎意料的事态下，孩子们讨论，互相观察，从现实情况开始推理解密。
不久，12个人想死的理由渐渐明了，他们查出的结论是什么。
他们聚集到此的真正理由是...。