The boys (Mike, Dustin, and Lucas)
Will's best friends were our primary storyline in Season 1. After his disappearance, we became well-acquainted with the three of them: good guy Mike Wheeler, funny boy Dustin Henderson, and straight man Lucas Sinclair. They were with Will on the night of his disappearance and were collectively dismayed in his absence. After coming across Eleven in the rainy woods, they took her in, and used her intelligence about the Hawkins National Laboratory to inform their search for their missing friend. With the help of their teacher, Mr. Clarke, they created a sensory deprivation tank for Eleven, which allowed her to mentally re-enter the Upside Down and locate Will. Eleven sacrificed herself to close the portal between both worlds and save her friends, leaving a heartbroken Mike -- with whom she shared a mutual attraction -- and the other boys to feel a grateful sorrow in her absence. But they happily joined Will, who was recovering in a hospital, and were all reunited in the end, sharing in on a new game of Dungeons & Dragons.
What's next? Though Will will happily re-join their friend group in Season 2, Mike will be in mourning for his friend Eleven, according to actor Finn Wolfhard. Dustin and Lucas will also crush on a new girl who enters the friend group: Sadie Sink's Max.
"She's this sort of skater punk girl, and Dustin and Lucas end up kind of falling in love with her. And she sort of gets into the group, and I'm not really happy with it because I'm kind of envious because they're in love and I'm not," Wolfhard told People of new girl Max.
The trailers also indicate that Dustin will acquire some sort of pet from the Upside Down, and will also join forces with Joe Keery's Steve. And given the season's Halloween release date and setting, let's not forget about the team's Ghostbusters costumes, which was the first image released for the upcoming season.