At the most dangerous border of Runeterra - the junction of the waters of Ionia and the Shadow Isles, there hangs a small island called "Twilight Island" and its vital lighthouse. The lighthouse keeper Elaina Twilight Sentinel relies on the "Twilight Crystal" inherited from her family to maintain the light of the lighthouse. This light is weak but can dispel the thin black fog, providing the only shelter for ships passing through this dead sea. However, the energy of the crystal is decaying at an unprecedented rate, and the black mist has become extremely active and corrosive, like an awakening giant beast. There was no news from the supply ship. On a stormy night, a merchant ship was almost swallowed by the black fog under the suddenly dim light of the lighthouse. In order to protect the island, protect the lives of the past, and to explore the truth behind the strange movement of the black fog, Elena must drive the fragile boat "Morning Dew" alone into the depths of the dangerous sea that even Ionian fishermen regard as forbidden territory. She needs to find the legendary and rare "twilight seaweed" that can recharge crystals while surrounded by twisted and mutated sea creatures. In this uncertain journey, she will discover the abnormal withering of seaweed, encounter mysterious predators that have never been recorded, and finally, inside the lighthouse crystal, touch a dark pulse that makes her soul tremble and is connected to the origin of Shadow Island. The duty of guardianship and the eroding shadow push Elena into the center of the storm.
