The first Elder Scrolls Adventure will take place after the events of Khenarthi's Roost in Elder Scrolls Online. The Silvenar has been assassinated using Daedric poison by the Maomer to ensure that they can finalise their Tempest mission to summon a hurricane to destroy more Dominion ships in order to maintain their control over the seas and Khenarthi's Roost (an island belonging to the Khaijit). The Green Lady was persuaded to spare Ulondil, the ambassador and mer responsible for the assassination, and he was instead imprisoned and interrogated. However this didn't stop the mighty Tempest ritual from being undertaken where the Maomer fed storm energies into a mighty storm-slave who was designed to explode and wash the island over with such energy - tearing apart the mountain to the north and wiping off all life forms barring the Thunder Bugs. This ritual was undertaken while a number of Maomer were assaulting the island -- some of whom unknowing of their likely death.
The PCs, themselves, were found adrift in a rowboat having been on a ship that had been destroyed by the hurricane and miraculously having survived.
The Ebonheart Pact, however, has other plans. Seeing the establishment of a Naval Base, they had their most powerful Dunmer Mages open a portal to Khenarthi's Roost where they sent three Dunmer mages and two Nord swordsmen to investigate. Using mystical illusions and stolen uniforms, they appeared to be Altmer Members of the Dominion Marines. Through quick investigation they located some of the most important people in town as well as Captain Irinwe's maomer ship which cowered in the northern isolated stretches of the island.
The Dunmer, Mivrose Rilrethi, donned the captain's likeness and stole aboard her ship. He lay an alchemically treated handkerchief to her mouth and when she fell unconscious he placed her in a chest and had the crewmen take the chest down to a room belowdecks which she locked. Since the ship had fewer crewmen (too many slaughtered in the attacks ashore), it was easy enough to refuse the crew that one room.
The Dunmer, Galydasea Krevyn, forged a writ from Headwoman Harrani so that she could enter the Maomer embassy where Ulondil was held imprisoned and feed him drugged wine. During a gap in the guard's change, she ingested a Potion of Strength so she could pick up and carry Uldonil back to the ship.
The Nord, Kottami Sabletongue, simply strode into the Chancery to speak with Headwoman Harrani alone and using his feigned rank of captain, convinced her of potential treachery in the ranks. He led Headwoman Harrani out of the building, using the whispered conversations of other guards as evidence of their illdoing, and then while they were out of sight of all, he struck her over the back of the head and hid her in a cart that he pulled all the way back to the ship.
The Nord, Hamasel the Innocent, an ironic name if ever there was on, drew the attentions of Vicereeve Pelidil over sincere and shared distaste for Khajiit food and drink (too sweet). When they went for a walk together, she clubbed him over the back of the head, threw him in a bag, and carried him back to the ship.
Evuliban Dresnimn, however, had been speaking to Gathwen, Rurelion's Apprentice and member of the Mage's Guild. He learned how she was part of an expedition to the Mourning Springs Temple on Khenarthi's Roost with her master, Rurelion, but they disturbed an ancient maomer mage called Uldor and one of the two of them had to offer themselves up as a suit so that he could be entombed once more. Rurelion was the one selected to be entombed with him. Gathwen still misses him terribly and is eager to find a way to free him yet leave Uldor trapped. After all, as she will counsel, Rurelion is a fine teacher who is taught even some of Queen Ayrenn's advisors. Evuliban, curious about this possibility, questioned her further and learned that Uldor's brief freedom had been triggered by the mage, Ealcil's, removal of the mourning stone which produced a plentiful bounty of water that had kept Uldor locked in his body. Evuliban filled her head with fanciful information about a hidden temple rumoured to be in the northernmost stretches of the island and then while camped out there he drugged her wine.
Evuliban Dresnimn has a plan. While Mivrose Rilrethi and Hamasel the Innocent take the Serpent's Kiss back up to their place, Kottami Sabletongue, Galydasea Krevyn and himself will visit the Mourning Springs Temple to free Uldor and set him against Khenarthi's Roost and possibly Elsweyr itself -- knowing that he would likely wipe out them all out.
The PCs will be victims of this enterprise - kidnapped along with the others.
Adventure Part 1 - Retaking the Viper
Adventure Part 2 - Return to the Roost
Adventure Part 3 - Revelations of the Tomb
PS. For those who are interested in running this adventure, be aware that I am using my own mix up of the World of Darkness. Don't worry, though, you could run it in Pathfinder using these custom rules and simply advise the players to pick classes that fit the Elder Scrolls universe. Or you could run it in any other custom system and simply use the adventure itself, if you like.