Sheriff Reyes assigns Abbie a case involving a mysterious suicide at Tarrytown Psych. Unfortunately, Ichabod has caught the flu and is in no condition to go anywhere.
Since Jenny had been a patient at Tarrytown, Abbie decides to take her along for advice on the case.
Once at Tarrytown they visit Captain Irving, who assures them he's not responsible. The Captain assure them he's still in control of his actions.
While going through video surveillance, the Mills sisters realize their mother's spirit was present in the victims room.
Abbie calls Hawley for assistance with the case, due to Crane's illness. Needless to say, this doesn't go over well and Ichabod roll his eyes at Hawley.
Nick brings some tasty Matzoh ball soup with him. However, it was laced with sleeping pills so Crane can rest. Before falling asleep though Ichabod informs them that Tarrytown was built in a specific area between us and the spirit world. He figures Moloch conjured up Mama Mills to pray on their resolve.
Elsewhere, Henry does a fantastic job of preying on Katrina's guilt. The villain manages to manipulate his mother into carrying baby Moloch. The demon's touch quickly infects Katrina and he skin begins to blacken.
Back at Tarrytown Psych, the Mills sisters and Hawley stop a patient from committing suicide. Mama Mills' spirit appears and Abbie is transported to an abandoned section of the hospital.
Jenny discovers a clue their Mama's spirit left behind which leads to an old video recording. This recording is a therapy session of Lori Mills. In it she talks of nurse Lambert who was a killer back in the 1950's.
The sisters return to the abandoned hospital wing for clues, as this is also where Mama Mills' cell was located. It isn't long before they uncover a drawing of themselves and their mother's spirit reappears.
Mama Mills tells her girls that Grace Dixon (their ancestor's) journal holds an incantation for sending this "angel of death" back to hell.
While Lori Mills and the evil nurse fight Jenny performs the incantation defeating nurse Lambert. However, Lori Mills' spirit vanishes as well.
The sisters are reunited with Ichabod and along with Hawley decide to summon their mother one last time. They finally understand Mama Mills fought until the very end to protect her girls. The demon, Moloch, sent the evil nurse to finish her off.
On their way out of the hospital, they come across Captain Irving who has managed to escape.
Katrina had been working on a spell to kill the demon child. However, when she approaches the crib it is empty. The child has grown and now appears to be 7 or 8 years old. Is Katrina inadvertently nourishing Moloch?