Kids on bikes fighting interdimensional monsters, which is basically what every eighties kid pretended was happening anyway.
Fun fact: The Duffer Brothers were rejected by 15 to 20 networks and studios before Netflix said yes.
Half the episodes start as a normal show and end somewhere you genuinely cannot explain to anyone the next day.
Fun fact: Donald Glover played Teddy Perkins in full prosthetic whiteface and went completely uncredited for the role.