Warning: Spoilers ahead for Stranger Things season 5, Volume 2!

Stranger Things season 5 has finally solved a mystery surrounding Will and the hive mind, confirming a theory that existed since season 2’s debut in 2017. Volume 1 revealed Will’s powers through his connection to the hive mind, but that link has always been much stronger than we thought. Will wasn’t just a spy for the Mind Flayer and Vecna in season 2; he also had another key role.

In Stranger Things season 5, the Party notably uses the intricate tunnel system under Hawkins to travel around town. Dr. Kay is still searching for Eleven, and the military has locked down the entire town, so the Party moves around in secrecy, if possible. While the tunnels may no longer be needed soon, season 5 does explain how they were actually created.

Theory Confirmed: Will Built The Tunnels Under Hawkins In Stranger Things Season 2

Mike and Will in Stranger Things season 2Image via Netflix

After using his powers again to save Max and Holly from Vecna, Will gets stuck in a trance while trapped in Vecna’s mind. During Stranger Things season 5’s “Escape from Camazotz” episode, Vecna reveals that he intends to use Will as his spy, as was the case in season 2. However, Vecna also refers to Will as his “builder,” confirming a long-running Stranger Things theory.

It turns out that Will was the one who built the tunnel system under Hawkins during the events of Stranger Things season 2. More specifically, Will was being manipulated by the hive mind, building them as he was asleep. Through Vecna’s control, and seemingly not the Mind Flayer, Will would tap into powers through his connection to the hive mind and use the vines to dig out the tunnel system.

It was clear that the tunnels were the cause of something related to the Mind Flayer, but Stranger Things never fully explained how the tunnel system was built. In addition to revealing what the Upside Down really is, season 5 has also uncovered the tunnel mystery, confirming the theory that Will was responsible, albeit through the hive mind’s influence, all along.

Why Vecna Used Will To Build The Tunnels & What It Means For Stranger Things Season 5

Stranger Things season 5 volume 2 VecnaImage via Netflix

By weakening Hawkins and creating more rifts from the Upside Down, Will unknowingly made it easier for the Demodogs to enter Hawkins. So not only was he acting as the spy during the events of Stranger Things season 2, but Will’s work building the tunnels put his family and friends in more danger.

The tunnel system also allowed the Upside Down to spread deeper into Hawkins, which was Vecna’s goal. By creating more Upside Down rifts and weakening Hawkins, Vecna was progressing with his plan to merge his world, the Abyss, with the normal world. To do so, he was using his first vessel, Will, to do much of the work, and he intends to finish his mission with the rest of the kids in Stranger Things season 5.

In Stranger Things season 5, Volume 2’s ending, Vecna takes control of the kids’ minds, and it’s likely he will use them the same way he used Will. As they become connected to the hive mind, Vecna essentially becomes stronger, especially now that he has an entire army of vessels to “reshape the world” for him.

Volumes 1 and 2 of Stranger Things season 5 are now available on Netflix. The series finale releases on December 31, 2025!