It's Wednesday morning and Leaf is visiting her friend Arthur, who is in a hospital bed, after damaging his leg during his adventures in Tuesday's treasure tower. Under his pillow, Arthur finds an invitation from Drowned Wednesday.The two friends are swept into the House via the Boarder Sea, however Leaf is taken by a ship, and Arthur is left clinging to his bed, which is in danger of sinking. He is rescued and soon finds out that unlike Monday and Tuesday, Drowned Wednesday is herself a tortured soul, and the first of the Morrow Days to wishes to follow the Will, and allow Arthur to become Rightful Ruler of the House. However, with the aid of magic, Arthur finds out that Leaf is abroad a ship named the Flying Mantis, where she becomes part of the crew and is later attacked and taken by the evil pirate Feverfew. With the aid of the crew of Moth and a group of Raised Rats, Arthur must find Feverfew's secret hideaway, free Leaf and the third part of the Will, after which Drowned Wednesday has promised him the Third Key.But, is Wednesday all she says she is, and will she keep her promise and freely hand the Key over to Arthur, and what has happened to his friend Suzy?