Every theory is incorrect. Just completely off the mark.

After season one, he overhears people talking about Will Byers and knows that Steve got the shit beat out of him by Jonathan and figures pretty much what everyone else does. But then, he catches all three of them hanging out in secluded corners, whispering quetly and leaning, pulling apart swiftly the couple of times they notice him, and he gets other ideas.

He knows Barb went missing, and rumor has it she was last seen by Nancy at the Harrington house. Everyone seems to have brushed it off, the search ongoing, but Eddie gets it in his head that maybe they should look again. He pokes around the Harrington house a couple of times at night, but never finds anything besides a closed pool.

When season two happens and the whole thing with Hawkin's Lab is revealed, he feels both relieved and a little dejected. He really thought he cracked something there, and thinking Steve might have been a murderer was really doing wonders to squash his crush.

But now Eddie is convinced that the leak reached the Harrington house too, because nothing else explains the sudden change in personality. He's actually convinced that everyone in town is slowly being poisoned because so many people are acting strange these days, talking about feral rats and murdered journalists and the bad omen of Halloween.

Eddie makes monthly trips to the closest city for almost a year, demanding that Wayne and him only drink the bottled stuff. He tries to get his friends to do it too, but they all argue that if the water was poisoned, they'd all already be dead anyway.

Eddie has a very complicated home set up for music that includes some pretty powerful radio equipment, knowledge provided courtesy Scott Clark's AV club back in the day, to pick up radio channels from the bigger cities. One day he's surfing for some new channels when he picks up some strange frequencies. It's gibberish to him, but he's pretty sure it's some kind of language.

He makes the guys come over and try to figure it out, and they identify it as Russian pretty quickly. Their combined efforts only get them a couple of strange words before it abruptly cuts off. Less than an hour later, they're all getting the emergency broadcast about Starcourt burning down.

Eddie doesn't believe for a second that it is a coincidence, and with Steve and his merry gang being the only survivors, he knows he has to be involved somehow.

He's always wondered why Steve had to have a job with parents as reach and influential as the Harringtons. One late night while he's ruminating on it in his bed, it hits him.

😭😭😭😭😭😭😭😭