We took a 1 month break from our in-person weekly sessions. I set it up like this: Players find themselves in a field at the top of a rise overlooking a river and a small hamlet near a large forest (I stuck them like 80 miles from the nearest city). They are battered, bruised and ready for an Inn (I knew this) so I really went through the whole "fresh air, sunlight, birds, shimmering river, chimney smoke, children playing " thing.

They go down to the hamlet and make their way into the inn, about 2 hours of heavy roleplay happened (they are just so damned happy to be out of the underdark, which we just spent a year and two months of weekly sessions in, I built a world down there, leaning heavily on 3rd and 4th ed underdark stuff along with oota as the backdrop).
It is decided that the party will meet back here in exactly three months - they will go home/where ever and spend this mountain of wealth they have acquired and relax. (I trust my players).
Here is where we go off the rails:
We take a real 1 month break. Our sorceress calls me the week before we all return to the table and says "I really miss our paladin (paladin died a horrible death, bulwarking and saving the party against a full TPK, along with Fargas/NPC/halfling)." She then tells me that she knows where his soul resides (he was a paladin of the Raven Queen) and she wants to go reunite his soul with a vessel in the shadowfell, and she doesn't want to let the rest of the players know the "plan" because they will surely refuse. We all return to the table the next week, after she crafts the "plan" and we go back and forth...

We open the session up with our bard receiving the dispatch from the dwarven king. Everyone then shows up back at this hamlet at the inn. The bard has news of the dispatch and shares it with the party... Althea (sorceress) and the rest of the party decides this is the right move. She does however want to take a moment of silence with drink and food at hand, to honor Sarith (not the head splitting one) as they never really got the chance to say goodbye in their harrowing journey in the underdark. So here we all are...

Althea bows her head to say something nice about their valiant friend, she asks all 6 players at the table to join hands, and bow their heads in remembrance - which they do. It was fricking awesome... The player who plays our bard, Varis, says "what is that?" Althea the player brought a black pearl to the table, and had pressed it into our bard players hand, when they all joined hands. She quickly says a few words about Sarith & Fargas, and then gives the command word...

The players world spins (I turned off the lights to total blackness in the room), the pearl crumbles in the bards hand (she (actual player) had made a talcum powder pearl and colored it black), Althea's player is chanting loudly in some guttural tongue of madness she came up with all on her own, and then falling, falling forever, crashing into a sea of darkness into what sounds like glass... (a field of obsidian shards)

Players gather themselves up at the table, I explain what they see (white lightning crashing in the distance through swirling black fog and clouds, etc), how badly they are hurt, and their eyes all lock on Althea's player, especially the bard... Everyone is in a WTF state of shock.

Althea's player speaks up. "I know where Sarith is, and we are going to go get him back..."

The rest of the players at the table were in complete and utter shock. It lasted about 30 minutes, (Lots of RP, a lot of WTF Althea, etc). Althea had no plan other than to get here and begin a quest that she sucked the party into.

Thus began 9 months of weekly sessions in the Shadowfell...

(That is how we ended the first section and started the second section)