Mad Men Season 7 has been full of an enigmatic series of events that certainly has left fans in awe of what will happen next. Episode 4 of the final season presents Don Draper in another exciting open-ended scene. In this episode he reportedly calls an anonymous friend. Is it from Sterling Cooper? Will Sylvia Rosen return?

In Episode 3, Don made an unexpected comeback to a group of unwelcoming associates at Sterling Cooper & Partners. It was certainly not his day and Peggy Olsen was not his greatest fan. "I can't say that we miss you," she said.

As a result, Don was demoted under Lou Avery's management. It was a tough deal - not meeting clients alone, no office drinking, and running a script during meetings are just some of the informal deals he got into making his stay at the firm all the more miserable.

His relationship with Megan is also on the verge of falling.

Surprisingly, Don made a call to an anonymous person. The curtains were closed even before audiences got a decent hint of who was on the other line. He asks, "Are you there," then hangs the phone.

Episode 4's The Monolith provides fans another round of puzzles to decipher. There are only two possibilities of who Don was talking with over the phone. It could be an old colleague at Sterling Cooper & Partners or Sylvia returning for a good reason. What is certain is that Mad Men producer Matthew Weiner wants Linda Cardellini (Sylvia Rosen), Don's love interest on the series, back on the final season.

What's in it for Sylvia and Don this time? Mad Men Season 7 Episode 4 The Monolith airs on May 4, 10 PM EST on AMC and can be watched online by live streaming by clicking here.