Will is the son of Lonnie and Joyce Byers and the younger brother of Jonathan Byers. …
On the night of November 6th, 1983, Byers was abducted by the Demogorgon and taken into an alternate dimension dubbed the Upside Down.
For a week, Will evaded the creature while his family and friends desperately searched for him.
In the mean time, here is the way Netflix will celebrate through the day with various info drops: