IT: WELCOME TO DERRY Episode 4 Finally Dives into Pennywise’s Terrifying Origin; Midseason Trailer Released

The fourth episode of It: Welcome to Derry arrives with the moment fans have been waiting for. After weeks of building dread, the series finally uncovers the true origin of Pennywise while pushing the story toward a frightening new confrontation. There is also a midseason trailer that previews the chaos still to come, and it looks intense.

Episode four, titled “The Great Swirling Apparatus of Our Planet's Function”, wastes no time reminding viewers why this universe continues to grip horror fans. Pennywise circles the young leads with a level of menace that pushes the series into some of its most disturbing imagery yet.

Will’s storyline sets the tone. During a quiet fishing trip with his father, a familiar red balloon drifts into view. The moment he is left alone, the entity closes in. He is yanked beneath the water by a grotesque interpretation of his father who hisses a chilling prophecy about fire. The real father pulls him out at the last second, but the damage is done. The creature has marked him.

Lilly’s friend Marge faces her own nightmare when a harmless prank on Lilly spirals into something horrifying. Her eyes burst forward on long stalks, and in a frenzy she rushes to the school’s machine shop and tries to sever them with a buzzsaw. Panic spreads fast and Lilly is blamed, though the truth eventually surfaces.

The episode then pivots toward the biggest reveal of the season. Hallorann dives into the mind of Rose’s nephew Taniel, unlocking the long hidden history of the creature haunting Derry. The sequence uncovers an ancient story of Pennywise.

We learn that millions of years ago an evil presence was cast down and bound inside a falling star that split open when it hit the Earth. A spirit escaped until the first ancestors discovered the crater. They realized the rock itself was a cage and that its pieces carried power. The Native Americans forged weapons from the stone to contain the entity and force it to remain within a defined territory.

When settlers arrived they ignored the warnings and were wiped out, giving the creature strength and allowing it to expand its reach. A group was later sent to eliminate the being, but Pennywise slaughtered every one of them.

Its lair was eventually found, and the shards of that fallen star were planted in the woods that would become Derry, sealing the entity within the land.

This episode confirms that Pennywise is trapped there and cannot escape as long as the shards remain where they were buried. General Francis Shaw wants to dig them up, convinced the military can weaponize the creature and use It against America’s enemies.

Thanks to Hallorann’s psychic dive, the group now knows the path to the lair starts at 29 Neibolt Street, setting the stage for what appears to be a violent showdown in next week’s installment.

It: Welcome to Derry is doing an awesome job expanding the world of Stephen King’s iconic novel and builds upon the tone and lore established in filmmaker Andy Muschietti’s It films. The cast includes Taylour Paige, Jovan Adepo, Chris Chalk, James Remar, Stephen Rider, Madeleine Stowe, Rudy Mancuso, and Bill Skarsgård, who returns as Pennywise.

The series comes from Warner Bros. Television and was developed for television by Andy Muschietti, Barbara Muschietti, and Jason Fuchs. Muschietti directs four of the nine episodes, and the show airs on HBO with streaming available on HBO Max.

The first four episodes of It: Welcome to Derry are now streaming on HBO Max.