West End version

The following describes the West End version of "The First Shadow":

Prologue

On October 28, 1943, the United States Navy conducts a classified experiment aboard the USS Eldridge, attempting to use a force field to render the ship invisible to enemy forces. Instead, the vessel is transported to the Abyss, where the crew are attacked by hostile creatures.

Chapter One: The Girl from Nowhere

On October 1, 1959, the Creel family, consisting of Victor, Virginia, Henry and Alice, move from Nevada to a new home in Hawkins, Indiana, on the first day of the school year at Hawkins High School. As the family settles in, Henry explores the attic, bringing with him a spider he keeps in a jar. While there, he unintentionally psychically connects to a radio belonging to Patty Newby, daughter of Principal Newby, as she prepares for school.

Henry arrives at Hawkins High, where he is introduced to other students by Walter Henderson, who alludes to an incident from Henry's past in Nevada. Henry struggles socially but quickly forms a connection with Patty. That same day, the school holds picture day and auditions for the upcoming production of Dark of the Moon, directed by Joyce Maldonado, who encourages students to participate.

That evening, Henry hides in the attic and overhears his parents arguing about him. He becomes overwhelmed by the influence of a shadowy presence, and his mind enters what he calls "the battlefield". Under its influence, Henry kills several animals in the area, including Claudia Yount's cat, Prancer.

At church, Claudia announces Prancer's death and offers a $100 reward for information; James Hopper Jr. and Patty's brother Bob hear about the reward and begin investigating. Henry and Patty speak privately in the church confessional, discussing their mothers and their loneliness. Henry promises to turn his nightmares into something good for her and creates a vision in which Patty imagines her mother performing as a singer in Las Vegas.

As the animal deaths continue, Jim and Bob discover Prancer's remains, and the investigation expands. These events coincide with the first rehearsal of Dark of the Moon, during which Jim questions several students, including Ted Wheeler, Alan Munson, and Henry. Jim dismisses Henry as a suspect but unsettles him by calling him "creepy," prompting Henry to flee to the school bathroom. There, Henry experiences another encounter with the shadowy presence, which takes the form of Patty, before the real Patty arrives to comfort him. The two share a kiss.

Later, at Melvald's Diner, Jim theorizes that the killer may be reenacting Dark of the Moon. Henry demonstrates telepathy to Patty by describing the emotions of the other teenagers and agrees to help her search for her biological mother. Joyce and Jim argue over Jim's motives, while Bob connects the animal killings to unusual radio interference.

At home, Virginia confronts Henry and slaps him after accusing him of inappropriate behavior with Patty. Meanwhile, Bob introduces his Directional Antenna Device (D.A.D.), and Joyce, Jim, and Bob trace the source of the strange radio signal to the Creel house.

Henry attempts to use his powers to track down Patty's biological mother. As he does this, and while inside the void, he loses control and is once again visited by the monster. This frightens Patty, and when her father walks in and witnesses the scene, he is attacked and almost killed (by Henry controlled by the presence). Patty is able to encourage Henry to fight back by telling him that she believes he is good and that she loves him. Henry responds that he loves her too and is able to end the situation, but not before Patty's father is blinded and seriously injured. Mr. Newby is sent to the hospital, and Henry's mother Virginia sends Henry to Dr. Martin Brenner. It is revealed that she was supplied with drugs by Brenner; under the influence of these drugs, Virginia told Brenner everything about her son. When Mr. Newby wakes up, he tells Patty that Henry saved him from the monster. Mr. Newby draws a picture of the shadowy entity on a piece of paper and gives it to his daughter: it's the Mind Flayer.

Chapter Two: Captain Midnight

Brenner takes Henry to Hawkins National Laboratory, where the two discuss the past:

It is explained that Brenner's father was the captain and sole survivor of the USS Eldridge experiment, who returned to the normal world with significant injuries and a unique blood type. Upon learning of this, his son Martin devoted himself to learning the truth behind the incident and established the Nevada Experiment, an attempt to reproduce what had happened to the Eldridge.

However, one of the personnel stationed at the Nevada military base was a spy for the Soviet Union. They managed to escape while stealing vital technology, transporting it to a Nevadan cave. At this time, an 8-year-old Henry and the Creels lived nearby, in Rachel, Nevada. While exploring the Nevadan caves and playing with a spyglass, Henry stumbled across the stolen technology when it unexpectedly activated, transporting him to the Abyss.

In the Abyss, Henry was exposed to the influence of the shadowy entity. Though Henry returned home after 12 hours, he now possessed a unique blood type and had a changed personality. Brenner was later able to track Henry down thanks to Henry dropping his spyglass in the caves.

Henry, using a sensory deprivation chamber, shows Brenner a humanoid creature through the Void. Brenner sees this creature displayed on a screen, and Henry convulses. Brenner then tries to force Henry to kill a prisoner, but Henry breaks down and ends up stabbing two guards. After this, Henry tells Brenner that he can let him go. Brenner understands that the boy is devoted to someone and therefore cannot kill; later Brenner realizes that this person is Patty and vows to find and kill her.

Henry returns home, but senses that his family is not happy about his return. Using his powers, he reads his mother's thoughts and understands that she wants to send him back to Brenner. Henry gives into the shadowy entity's influence, which results in the deaths of Virginia and Alice.

In the aftermath of Virginia and Alice's deaths, Victor is blamed for the killings. Some time later, Henry walks to Hawkins High School to save Patty from Brenner, where the performance of Dark of the Moon is in progress. Atop the stage rafters, Henry reunites with Patty only to be interrupted by Brenner, who appears on the other side of the stage. Brenner says that Patty is his weakness, and Patty tells Henry not to listen to him. As Henry struggles for control, he informs Patty that he managed to find her birth mother, a singer at the Stardust Casino in Las Vegas. Feeling overwhelmed, the shadowy entity once again takes control of Henry, and Henry throws Patty off the rafters. Brenner takes Henry back to Hawkins Lab, Patty is taken to the hospital, and Victor Creel is accused of the murder of Virginia and Alice based on Joyce, Bob and Jim's assumptions about the animal killings.

In 1960, Joyce and Jim bid farewell to each other as the latter is shipped off to fight in Vietnam.

Epilogue

Some years later, an older Henry is back at Hawkins Lab and is restrained. Using the Void, Henry discovers that Patty survived her fall and was discharged from the hospital, though now needing to walk with a cane. Henry observes her in Las Vegas, where she meets her mother backstage after a performance at the Stardust Casino; Patty and her mother recognize each other and embrace.

Brenner informs Henry that the blood transfusions administered to the test subjects have been successful; as a reward, Brenner frees Henry from his restraints. In the Rainbow Room, Henry is introduced to one of the children; Henry remarks: "What's your name?" (He takes her arm) "Eleven, it's nice to meet you, I'm here to help." Lightning flashes and the silhouette of Vecna appears on the back wall.