Here’s how the first part of this series shall play out.
It begins with Pennywise in it's lair making contact with it's master the Crimson King. The Crimson King tells Pennywise it's time to wreak Havok on the world, and gather as many allies as possible, and find a door to free the Crimson King and the forces of the Red so they will bring Hell on earth. Pennywise happy to hear that, but the Crimson King warns Pennywise if it fails, he would be what It will fear more than being un afraid. Pennywise promised and summoned fourth the Djinn, and Horney the Clown and tells them to cause havoc while also looking for recruits for the Crimson King and the Red.