The trilogy finale "that combines elements of Atlantis, alien-earth population theory, and King Arthur legends . . . Engrossing, suspenseful, and fun" ( Booklist ). Sixteen-year-old Corwin has been telepathically linked to mermyd Nia ever since she arrived on the shores of Wales. Their bond is also shared by Gobaith, the young Farworlder creature. Now, the time has come for Corwin to embrace his half-mermyd ancestry and follow his friends to a place beyond his imagination: Atlantis. The undersea city has been taken over by an evil mermyd king who has killed the reigning Farworlders and implanted the source of their alien powers into his own body. The wicked king's ambition has grown beyond the confines of the sea, and dry-lander kingdoms are his next conquest. Only Nia, Corwin, and Gobaith can stop him. Their only hope to save Atlantis—and the world—rests in finding a magical sword. But to find this weapon of peace, they'll have to wage war . . . Praise for the Water trilogy "Dalkey's intriguing marine world brims with descriptions of Atlantis and mermyd life." — Publishers Weekly on Ascension "An exotic undersea world is given vivid life . . . The exhilarating twists and turns carry readers gasping into a stunning cliffhanger that will leave them clamoring for the next installment." — Kirkus Reviews on Ascension "Enjoyable. Buy it to hook readers into Arthurian fantasy." — School Library Journal on Transformation