Dustin Henderson

On the night of November 6, 1983. Dustin was playing Dungeons and Dragons aka d&d with his friends Mike Wheeler, Lucas Sinclair and Will Byers. Later that night, Will went missing. Will's disappearance prompted Dustin, Mike, and Lucas to go searching the woods for him, which led them to come across Eleven instead. They discover Eleven has psychokinetic abilities, which allow them to find out that Will is trapped in an alternate dimension known as The Upside Down. Though initially skeptical of Eleven's capabilities, he grows to admire her and defends her from Lucas's skepticism, but still teases Mike's fondness of her. Dustin, Mike, Lucas and Eleven witness Will's body being recovered from the lake, but then discover a transmission of Will singing in the Upside Down. The boys disguise Eleven to bring her to the Heathkit at Hawkins Middle School to be able to track Will. After discovering the possibility of the Upside Down is real, they follow their compasses "north" after a suggestion from Dustin in hopes of finding The Gate. They then discover that Eleven had been using her abilities to tamper with the compasses and lead them away from The Gate and imminent danger. This causes a disagreement between Lucas and Mike which ends with Eleven throwing Lucas away from Mike with her mind, causing Lucas to angrily storm off and Eleven to run away.

While searching for Eleven, Dustin and Mike come across school bullies Troy and James who threaten to cut out Dustin's teeth if Mike does not jump off a cliff. This is settled when Eleven arrives and saves Mike in mid-air and breaks Troy's arm. Dustin and Mike console Eleven and reconcile. The boys and Eleven head back to Mike's house, but are warned by Lucas via radio that the agents at Hawkins Lab are on their way to re-obtain Eleven. The group hides out at an abandoned junkyard until they are rescued by Chief Jim Hopper. After returning to the Byers household and meeting up with Mike's sister Nancy and Will's brother Jonathan, Dustin realizes that for Eleven to be able to locate Will in the Upside Down, they would need to build a makeshift Sensory Deprivation Tank. They sneak into Hawkins Middle School to use the facilities and learn that Will is alive, but barely hanging on. As Joyce Byers and Chief Hopper sneak off to infiltrate Hawkins Lab, the rest of the group remains stationary at Hawkins Middle School.

After a deal made by Hopper with Dr. Martin Brenner to be able to save Will, the group's location is given up to the agents of Hawkins Lab and they infiltrate the school. Eleven kills most of the guards but the scent of blood attracts the Demogorgon. Eleven used the last of her powers to kill the Demogorgon, but in the process ended up trapping herself in The Upside Down. Will is saved and the boys celebrate during Christmas by continuing their original game of Dungeons and Dragons.

After a successful night of Trick or Treating on Halloween night, Dustin arrives home to discover that his trash can is moving and making unusual noises. After looking inside the trash can, Dustin discovers a reptilian like creature and hides it in his costume Proton Pack. He places the creature in his turtle tank and names it D'Artagnan, or simply "Dart". The next day Dustin brings D'Artagnan to school to show it to Mike, Lucas, Will, and new addition to the party, Maxine "Max" Mayfield. Dustin concludes that he has discovered a new species, but Will recognizes the creature from the Upside Down. After Mike attempted to attack Dart, Dart runs off throughout the school. Dustin eventually finds Dart and hides him under his signature cap and lies to his friends, saying he has not seen it. After returning home from school the next day, Dustin discovers that his new pet is actually a Demogorgon and has killed his family cat Mews. Dustin lures Dart out of his house and into the storm cellar. When he radios his friends for help, he is unable to reach them and leaves Dart in the cellar while he physically searches for them. After he fails to find either Mike or Nancy, Dustin runs across Nancy's boyfriend Steve Harrington and enlists his help. Once they arrive at Dustin's cellar, they find that Dart has grown yet again and broken free from captivity. Steve and Dustin lay bait for D'Artagnan on the train-tracks that lead to the abandoned junkyard. On the way, they bond while discussing how to talk to girls, and it is revealed that Dustin kept Dart in hopes of impressing Max. Steve and Dustin arrive at the junkyard and meet up with Lucas and Max, who assist in fortifying the abandoned school bus and laying a trap for Dart. Steve helps protect the group from the "Demodogs" until they are called away to Hawkins Lab. The group then heads to Hawkins Lab and regroup with Mike, Will, Nancy, Jonathan, Hopper and Joyce, and retreat back to the Byers household. The group attempts to question Will for a weakness by hiding him somewhere the "Mind Flayer" cannot track him. Will manages to subconsciously communicate to the group in Morse Code, deciphering his message to say "Close Gate". However, the Byers' house phone rings and gives away their location to the Mind Flayer.

The house becomes swarmed with Demodogs, but Eleven returns to the household and saves the group. The group then splits into groups to help defeat the Mind Flayer with one group going to exorcise the Mind Flayer from Will, and with Eleven and Hopper heading back to Hawkins Lab to close the gate to the Upside Down, leaving Dustin, Steve, Mike, Lucas and Max back at the Byers residence. They come up with a plan to distract the Demodogs by setting fire to some of the tunnels in the Upside Down to allow Hopper and Eleven to safely reach the gate. Before they can put their plan into action, Max's step-brother Billy Hargrove arrives at the house looking for his step-sister. Steve attempts to protect the kids and fights Billy, however Steve is badly beaten. Max sedates her step-brother with a syringe, then steals his car and drives her friends to the tunnels. The group arrives at the hub in the tunnels and sets it ablaze. They soon encounter Dart, who recognizes Dustin and does not attack him, allowing the group to pass as Dart and Dustin say a final goodbye. After the campaign, Steve drops Dustin off at his school's "Snow Ball", and gives Dustin some final advice before he enters. Unfortunately, Dustin is rejected by every girl he asks to dance. Seeing Dustin alone and devastated, Nancy asks Dustin to dance and offers him some advice of her own.

After returning from summer science camp, Dustin sets up an extremely powerful handcrafted radio that he created to talk to his girlfriend Suzie, and presents it to Mike, Eleven, Lucas, Will, and Max. Doubting Suzie's existence after failing to contact her, the other children leave Dustin alone with the radio. Shortly after they leave, Dustin comes across a Russian transmission.

After reuniting with Steve, the two of them, alongside Steve's coworker Robin Buckley, translate the message and conclude that it is a code. While spying on mall patrons to find any Russian spies, Dustin tells Steve that he should ask out Robin because he enjoys her company. While Dustin and Steve fail to find any Russians, Robin manages to break the code, realizing that the Russians have a delivery coming to Starcourt Mall's loading dock that night.

The trio spies on the armed guards, and, after narrowly escaping, decide to travel into the loading dock through the air vents during daytime, when the guards are not on duty. However, as none of them can fit through the vents, they enlist the help of Lucas's younger sister Erica Sinclair, who opens the door to them. However, as the group enters, the loading dock is revealed to be an elevator, which plunges downward with the four of them trapped inside. The elevator door opens to reveal a Russian base, and the group finds that the Russians are reopening the Gate to the Upside Down. Steve and Robin are captured, while Dustin and Erica narrowly escape through the air vents. Inside the air vents, Dustin explains the events of the previous two seasons to Erica. After Erica calculates how long it will take to get back to the elevator, Dustin convinces her that she is a nerd, and that she should fully embrace being one.

The two return to the elevator for supplies to free Steve and Robin. They succeed, but Steve and Robin are drugged so that they could be interrogated. The four hide in a movie theater, showing Back To The Future while Dustin calls Mike for backup, but is unable to give his location before his Walkie-Talkie's batteries run out. After the movie finishes, a Russian guard catches them. However Eleven, who finds Dustin's group using her powers, arrives with her group, just in time to stop the Russians from shooting them.

After a brief reunion with the rest of his friends, Dustin returns to his makeshift radio with Erica, Steve, and Robin to navigate Hopper, Joyce, and Murray through the air vents to shut off the machine opening the Gate. However, Planck's constant is the code to the machine's room, and as nobody can remember what it is, Dustin finally contacts Suzie. The two sing The Neverending Story by Giorgio Moroder before Suzie gives them Planck's constant, allowing the machine to be shut off, seemingly at the cost of Hopper's life. Three months later, while Dustin helps the Byers, Eleven prepares to move out of Hawkins, Lucas and Max tease Dustin about the song he sang with Suzie.