Four months after a classmate vanishes, Teddy, Phil, Lilly and Ronnie investigate missing children and strange events in Derry. Major Leroy Hanlon faces a cold welcome at Derry Air Force Base.

While Charlotte and Will navigate their new life in Derry, Ronnie worries about her father's fate.

As Leroy, Pauly, and Dick search for a new dig site, the kids attempt to get visual proof of the phenomena they've been experiencing.

As the kids face increasingly terrifying experiences, Charlotte attempts to advocate for Hank, and General Shaw escalates his efforts.

As the military descends on Neibolt Street, the kids head into the sewers with their own objective.

Dick is plagued by increasingly dark visions. Will faces his parents' disapproval, Marge stands up to the Patty Cakes, and Lilly's behavior grows erratic.

A vigilante attack on the Black Spot unleashes long dormant forces. In the aftermath, Dick helps uncover another crucial artifact.

As a dense fog engulfs the town – and General Shaw pushes ahead with his mission – the Hanlons, Rose, Dick, and the kids must work together to save Derry.