The Machine identifies a school teacher who witnessed a mob hit as their next POI and Reese and Finch rush to save his life.

Finch and Reese head to Atlantic City to protect the latest person of interest, an elderly gambler; Carter tries to clear another detective's name.

Finch and Reese team up with unexpected allies as they race to fix the machine; as Detective Carter tries to apprehend Cal Beecher's murderer, she finds herself up against HR -- a criminal organization.

Shaw must stay close to a 10-year-old girl with highly developed surveillance skills when she is identified by the machine; Carter's mission could be exposed.

The machine gives Finch 38 numbers at once; information about Carter's past is revealed.