There hiding something (FNAF SISTER LOCATION PT 2)

It's called “Sister Location“ because you're both locating your sister and it's literally your sister's location (a "sister location" refers to two or more locations (often physical stores or branches) that are owned or operated by the same parent company or organization. While they may be under the same umbrella, they typically function as separate, distinct entities, often in different locations or even operating under different brand names.)