The novel begins with Riggu Felis, European wildcat warlord of Green Isle, and his two sons, Jeefra and Pitru, attempting to kill an osprey, later known to be Pandion Piketalon.

This upsets Tiria greatly, and she is quick to listen when Martin the Warrior and High Queen Rhulain Wildlough appear to her in a dream, telling her the otters of Green Isle need her assistance and leadership.

After deciphering and scouring the Abbey for many clues with Old Quelt, Sister Snowdrop, Abbess Lycian, Brinty, Tribsy, and Girry, Tiria learns through another dream that she has to leave on her own, so she heads to Log-a-Log Urfa's encampment along with her father and Brink Greyspoke.

Along with the a number of hares of the Long Patrol, Tiria sails to Green Isle in Frunk's ship, the Purloined Petunia, and they meet up with Shellhound and his otter clans.

Leatho Shellhound is trapped in a burning tower, set afire by Riggu's mate, Lady Kaltag, who lost her mind after the loss of her son, Jeefra.

Anita Burkham of Horn Book said that Jacques' "trademark blend of folksy good humor and high-spirited action," and High Rhulain character's exhibits a "joie de vivre that earns them the loyalty of their many fans."