Riven is a puzzle adventure game and the sequel to Myst. Developed by Cyan Worlds, it was initially published by Brøderbund.Riven's story continues where Myst and its companion novel, Myst: The Book of Atrus, left off. Atrus needs the Stranger's help to free his wife, Catherine (Sheila Goold; voice by Rengin Altay), who is held hostage on the slowly collapsing Age of Riven. Her captor is Gehn (John Keston), Atrus' manipulative father and self-appointed ruler of Riven. Gehn is himself trapped on Riven, as Atrus and Catherine had previously removed all linking books from the Age; the very last book to be removed, linking to the Age of Myst, was the one they held to escape Riven. In the misbelief that it would be destroyed, they let the book fall into the Star Fissure, a rift leading out of the damaged Age of Riven into a mysterious, spacelike void. Catherine was later tricked into returning to Riven by her sons, whereupon she was taken hostage by Gehn. Eventually, the Stranger discovered the unharmed Myst book, sparking the events of Myst and, some time later, Riven.