The AMC Network has recently released the synopsis of "Mad Men" Season 7, episode 4 titled "The Monolith," which will air at 10.00 pm on Sunday May 4.

However, before we delve into the blurred summary, let's discuss the title of the May 4 episode. What does Matthew Weiner denote when he names the episode "Monolith"? In fact, it refers to a geological feature comprising a single massive rock, for instance, a mountain or a monument. Such geological formations are exposed to erosion - but they are extremely hard and a solid piece metamorphic rock.

If all this confuses you, just think of two familiar monoliths to give you an idea - a geological monolith - a half dome in Yosemite National Park, California, and, second, a monumental monolith - Aztec Calendar Stone, also referred to as the "Stone of the Sun."

So, how are these related to "Mad Men"? Well AMC says that Sterling Cooper & Partners will prepare for a special guest in episode 4. Don will contact an old friend, and Roger will deal with problems at home while Peggy will be underestimated.

All these are typical, as there is hardly any meat to "Mad Men" teasers. Of all that is mentioned in the synopsis, we are most intrigued about Don's plot. Who will Don contact - a friend at Sterling Cooper or possibly a lady from his past?

Based on the trailer, it was possible to predict that Don and Sylvia would reunite in episode 3. Similarly, in the promo released online, we hear Don speaking to an anonymous person, who is on the other side of the line.

We see Don asking "Are you there?" and subsequently hanging up the phone. Is it Sylvia on the other line?

All that we know is that "Mad Men" creator Weiner is sure to reprise the character of Linda Cardellini in Season 7, but then we are not certain whether she will make her debut in episode 4.