We Do Not Sleep Sgt Rook of GCPD's Internal Affairs unit is sent to investigate GCPD's Precinct 13. This precinct, is the home of the Detailed Case Unit, consisting of Lt. Weaver, Detective Corrigan, Detective Drake and consultants Sister Justine and Dr. Szandor Tarr. This unit reports dirctly to Commissioner Gordon, but has never recorded a single arrest!
The current case involves two young girls reported as missing. They recently returned home and GCPD dropped the case. But it seems that the girls came back changed. They speak only in an unidentified language, which Det Corrigan apparently recognizes and states that it not a living language.
This is a job for the "Midnight Shift."