FBI Child Specialist Claire Bennigan investigates several cases that revolves around an imaginary friend named Drill. She draws up some disturbing details.
Sean and his hostage Dr Maria Benavidez are lead to a secret location. Meanwhile, Claire ands piece together Sean's target.
Drill continues to play with Minx, Henry, and Harper. Claire looks into his identity, and Minx admits to the security breach.
Henry plays one final game with Drill, Claire and Wes race to stop Sean, and Henry's parents are shocked to discover he can now hear and speak.
Sean, Wes, Claire, and Lena studies Thomas' past to discover the way of eliminating Drill. Meanwhile, Drill threatens Thomas in a new host's body.