Martina Crowe was a Messenger at the Institute. She became an Executive before Mr. Curtain was forced to close his school. In the story, she passionately hates the members of the Mysterious Benedict Society.
In The Perilous Journey, Martina seems to be the boss of the Ten Men. But in the end, Mr. Curtain leaves her while he escapes. Greatly angered by this, Martina tells Mr. Benedictall she knows about Mr. Curtain's plans. Martina's information was limited because Mr. Curtain did not trust her.
Martina Crowe did not appear in The Prisoner's Dilemma, although she was mentioned a few times. She is taken into Mr. Benedicts home for questioning every so often, but otherwise is not mentioned in this book.
According to the illustrations of the Mysterious Benedict Society's companion book, Martina has a black ponytail and wears a green shirt and a pair of jeans and sneakers.
In the first book, she was described as a tall and athletic teenager with shiny raven black hair.