Treasure in the Royal Tower is a young adult novel by Carolyn Keene

Carolyn Keene

Carolyn Keene is the pseudonym of the authors of the Nancy Drew mystery stories and The Dana Girls mystery stories, both produced by the Stratemeyer Syndicate...

 in the Nancy Drew stories.

Plot summary

Nancy takes a vacation in Wisconsin when the library of the place she is vacationing at is vandalized. Nancy, along with her friends George Fayne

George Fayne

Georgia "George" Fayne is a character in the popular Nancy Drew Mystery Stories series. She is one of Nancy's best friends and cousin of Bess Marvin. Her real name is Georgia, although no one calls her that except her parents...

 and Bess Marvin

Bess Marvin

Elizabeth "Bess" Marvin is a character in the Nancy Drew Mystery Stories series. She is one of Nancy Drew's best friends, along with George Fayne, who is Bess' cousin. Bess and George are introduced to readers in the 1931 novel,The Secret at Shadow Ranch. Bess was originally described as having...

, must survive an unknown assailant while discovering the secret passageway's inside of an old castle.

Later, Treasure in the Royal Tower was made into a Computer (PC) Game where you can play as Nancy and find Marie Antoinette's tower.