The party prepared to enter Thelanis (see ST16. Secrets and Sequins). Tregin and Ying arrived, having decided to be fashionably late for the gala, but Amos Black elected to stay behind due to injuries. Before they headed in, they sat to briefly recall the sad tale of the Prince of Frost and Lady Sharaea; how he had once been a prince of the Summer Court, whose heart had turned to bitter ice when Sharaea had left him for a mortal hero, and refused to return to marry him as promised. After he had failed to capture them, they had made a pact with The Raven Queen to fling their souls far into the future to be reincarnated, and he hunted beautiful women that he thought could be his lost love, while also planning for the destruction of the mortals that he blamed for taking her from him. His realm was called the Vale of the Long Night, and he resided within it at the icy Fortress of Frozen Tears.
They gathered their equipment, climbed up the now-frozen waterfall, and followed Luna Lacewing through the portal at the top. On the other side, they found themselves in the skeletal ruins of a giant creature of some kind half-buried in the snow, the ribs extended far above them. The beautiful night sky above them was like nothing they had ever seen, full of bright constellations that they didn't recognise. Before they could work out where Luna Lacewing had gone, the quintet were attacked by a trio of crag cats, that pounced out of the shadows at them. Ying and Kuven went after one, while Sacha Cresswell galloped his horse at a second; El Graeve and Tregin stayed in the middle, trying not to get attacked by the third. Ying immediately managed to stun one, and pulled back to allow Kuven to finish it off, while he came back to help protect Tregin, but he was unable to stop the crag cat from knocking the wizard to the ground. Their bites and claws proved quite dangerous, but Tregin was able to douse one in acid, and the third fell to a combination of blows from Sacha Cresswell and Ying.
They paused for a break, during which Ying skinned the cats to give them something warm to wrap up in, and protect them from the winter cold. Meanwhile Kuven, who didn't need a break, managed to find footprints leading off in one direction, which started at the portal that they had entered through, and looked like they had been made by someone wearing snowshoes. The party decided to follow, which was slow going as they trudged through the snow in their makeshift cloaks, but eventually they crested over a hill to see a beautiful palace made of ice. They could see small figures walking around, which resolved themselves into guards when the party got closer. One of them approached them, and told them to follow him through the palace for an audience with the Prince of Frost. Along the way, they saw frozen in the walls of the fortress large numbers of adventurers, as well as many women in beautiful gowns; the captives of the Pale Prince.
They entered the Prince's throne room, and the guard closed the door behind them. Next to the throne was Luna Lacewing, looking scared. The Prince of Frost was annoyed at the interruption, and demanded to know why the mortals had entered his realm. He was not prepared to offer them Luna Lacewing so that she could return to face justice and close the portal that she had left open; he was quite pleased that his wintery realm was spreading into Eberron. He explained that Luna Lacewing was trying to return home to the Moonlit Vale, and had bartered for passage through his realm by offering a broach that apparently belonged to his lost love. He had not had time to examine it, or to ask the Sisters of Lament, if it were genuine. Not seeing a resolution, the conversation became heated, and ended with an arrow being fired at the Prince of Frost, who immediately responded in kind. He summoned himself a bow made out of pure ice, and fired arrow after arrow at the party, faster than they could react. Kuven managed to get to Luna Lacewing and grapple her, pulling her out of the way as Tregin threw multiple Fireballs at the fey Prince. This not only damaged him, but also melted the icy wall behind him, giving the party a possible escape route out of the room.
Sacha Cresswell was knocked unconscious by the arrows, but was revived with a Healing Word from El Graeve. Tregin's final Fireball managed to break through the wall just before he was also laid low by an icy arrow. Sacha Cresswell charged his horse across the room, using Lay on Hands to heal himself, while El Graeve also healed Tregin, and everyone headed for the hole in the back of the throne room. Kuven pulled Luna Lacewing through, while Ying was not far behind him. El Graeve grabbed onto Sacha Cresswell's horse as it also ran through, taking them to safety; Tregin was last out, using Dimension Door to teleport himself as far away as possible. The angry Prince of Frost was left in his ruined throne room and without the woman that had offered him a keepsake of his betrothed.
There was little time to recuperate though. The party made their way through the outer structures of the fortress, but quickly found themselves pursued by the two wraiths that had formally been Lady Sharaea's sisters, the Sisters of Lament. Realising that they were undead fey, El Graeve used Turn Undead to send one of them away, but they could not shake off pursuit of the other. The five of them made a stand in an outbuilding, and as the second wraith approached them, they attacked her as ferociously as possible. She took heavy damage, but before she was completely destroyed, she drifted through Sacha Cresswell and the building wall, and unleashed a mournful wail that immediately rendered El Graeve and Sacha Cresswell unconscious. Kuven was able to finish off the wraith, while Ying managed to stabilise El Graeve, who in turn then healed Sacha Cresswell.
This enabled them to make their escape, and they were unharmed for the rest of the way back to the portal. They decided to allow Luna Lacewing to stay if she completed the necessary ritual to close the portal, deciding that justice was less important to them than saving Eberron from an icy fate. And so she complied, letting them pass through the portal just before it completely sealed; not even the water that came through previously now appeared, so Argellan Falls lost its notable feature. When they returned, the party lied to Adira, saying that Luna Lacewing was dead and they had taken years in Thelanis, but she did not believe them. She merely stormed off to mourn her cartographer and right-hand, while the crew of The Demon's Mercy were left to ponder what to do next.