IT: Welcome To Derry season 1 episode 1 drops viewers in the 1962 town of Derry, Maine, long before what has been documented in the previous films. The show introduces a new cast of kids along with adult characters, including Lilly Bainbridge and Ronnie Grogan, and connects their realities to the growing evil that lies beneath the facade of Derry.
Disclaimer: The following article contains spoilers for the show. Reader's discretion is advised.
In the IT: Welcome To Derry premiere episode, Lilly and Ronnie escape a gruesome massacre in a cinema. Lilly, tormented previously by Matty Clements' vanishing and his voice in her drain, goes to see a film with Ronnie and two others.
The moment of projection unravels into mayhem as Matty is shown on screen with a distorted creature in his hands. This baby-monster bursts through and murders Teddy, Phil, and Susie, leaving Lilly and Ronnie as the only survivors of the massacre.
How does Matty vanish in the IT: Welcome To Derry season 1 premiere?

IT: Welcome To Derry season 1 premiere shows Matty breaking into the Capitol Theatre, getting caught by Cal, and subsequently hitchhiking out of Derry with a seemingly benevolent family en route to Portland. After they have gotten into the car, the peaceful veneer cracks as the mother in labor delivers a grotesque baby-monster.
Matty is eventually attacked and kidnapped into darkness, his pacifier falling into the sewer and bobbing under the surface of Derry. Four months later, his disappearance haunts Lilly, Phil, Theodore, and Ronnie, compelling them to seek out his disappearance. The cold opening implies that Matty did not leave Derry of his own accord but was taken by the evil that resides beneath the town.
His voice in the drain and later his appearance on the screen put him in both victim and vessel categories for the horror. The cliffhanger hints at his return and the fact that his vanishing was only the first in a bigger cycle.
Also read: Meet the cast of IT: Welcome to Derry
How does the theatre massacre in the IT: Welcome To Derry season 1 premiere fit into Derry's history of evil?

In IT: Welcome To Derry season 1 episode 1, the most terrifying scene occurs within the Capitol Theatre. There, Lilly Bainbridge, Phil Malkin, Teddy Uris, Susie Malkin, and Ronnie Grogan try to find out what happened to Matty Clements, who disappeared after watching the movie The Music Man.
Ronnie, whose dad runs the projector, shows The Music Man, the same movie Matty had seen before he disappeared. Halfway through the screening, ominous Matty materializes on screen with a white, distant face and clutching what appears to be a swaddled baby. The "baby" is then revealed to be a grotesque, winged creature that breaks into the real world out of the projection.
Panic breaks out as Teddy, Phil, and Susie are brutally murdered while Lilly runs out of the theater, and Ronnie hides in the projection booth. The two girls are the only survivors of the massacre. The sequence is a pivotal moment in the episode as it showcases a burst of supernatural horror that defines Pennywise's insidious presence and establishes the season's dark tone.
Also read: IT: Welcome to Derry creators react to Stephen King's praise
Is Hanlon's Airbase connected to the supernatural events occurring in IT: Welcome To Derry season 1?
Concurrent with the children's terror, IT: Welcome To Derry season 1 brings aboard Major Leroy Hanlon, a war-honored pilot transferred recently to Derry's northern airbase. Keen to be back home with his wife and infant son, Hanlon is treated rudely by racist subordinates such as Masters and cautioned by General Shaw regarding an unofficial "Special Projects" branch working on base.
Late one evening, Hanlon is ambushed in his quarters by marauding intruders who threaten specifications for the new B-52 bomber he is to test. Showing his combat skills, Hanlon repels them with assistance from his acquaintance, Captain Pauly Russo. The intruders escape, leaving behind the chilling inference that the airbase could be part of Derry's greater mystery.
The subplot reflects the racial tension, secrecy, and paranoia of Cold War America and quietly interweaves military ambition with the supernatural darkness that is spreading beneath the town.
IT: Welcome To Derry season 1 is available to stream on HBO Max.