Two costumed burglars shoot a woman on Halloween. They drill into the safe in her basement, where someone is confined. Max is visiting at Flippa's Halloween party, along with his son Dunde, both dressed as John Wick. Also there is Flippa's mother Princess. Grover and Adam investigate the murdered woman along with a dead burglar in the basement. The other burglar is running from the man in the safe and gets hit by a car. Lana, a missing high-school girl, is found dead in a submerged car. The power goes out as Noelani is about to perform the autopsy. The circuit breaker was tripped. The girl's body is gone when Noelani returns. Noelani blames herself for the missing body. Edith, the dead woman, had disappeared from the grid for 20 years. That's because she became a nun. But none of the nuns would say why Edith left the sisterhood. Duke reviewed Lana's case for McGarrett and Junior. They find two leading suspects in the case murdered with the initials "LN" near their body.  Dunde runs off with other kids while trick-or-treating with Flippa. Max said the DNA in the vault didn't match Edith's. Tani and Quinn tussle with the man from the safe, with Tani winging him. Mother Superior Decosta had two mismatched eyes, just like the man kept in the safe. Edith was raising the son with a genetic condition which the mother superior had given up. The third suspect, Zach, is attacked by a woman as he prepares to bury Lana's body. She's Lana's sister Emily, who throws him in the trunk with Lana and is submerging the car. Dunde offers the escaped man a lollipop. Then police surround him. Junior rescues Zach while McGarrett arrests Emily. Max and the Mother Superior calm down the man.