Young Indiana Jones and the Mask of the Madman was supposed to be the sixteenth young adult novel in the Young Indy series published by Random House, and the third by authors Megan Stine and H. William Stine.
Ultimately the book went unreleased, but some information has been archived in online shopping store product pages. The story was to be set in 1912 and found Indiana Jones and his cousin Lyle kidnapped by a Mexican cult.
Publisher's summary Edit
Searching for the missing Professor Dante, young Indy and his cousin, Lyle, learn that Dante may be the founder of a bizarre underground cult, and when they find him, they are forced to participate in a grisly ceremony.