In the 19XXs, beings known as "Impostors"—entities that mimic humans—appeared across the globe.

As the manager of an apartment complex, your duty is to monitor everyone who comes and goes.

Observe closely.

"Impostors" inherit the memories of the humans they replace and imitate them.

However, their imitation is never perfect.

Gather information using the TV and telephone, cross-examine visitors, and never miss the slightest anomaly.

Decide.

Will you let the visitor pass, or will you raise your gun?

Your decision directly dictates the fate of the residents.